Jim Galligan

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• Muthaiyan Shanmugam, M., Chaudhuri, J., Sellegounder, D., Sahu, A. K., Guha, S., Chamoli, M., Hodge, B., Bose, N., Roberts, C., Farrera, D. O., Lithgow, G., Sarpong, R., Galligan, J. J., & Kapahi, P. (2023). Methylglyoxal-derived hydroimidazolone, MG-H1, increases food intake by altering tyramine signaling via the GATA transcription factor ELT-3 in. eLife, 12.
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  The Maillard reaction, a chemical reaction between amino acids and sugars, is exploited to produce flavorful food ubiquitously, from the baking industry to our everyday lives. However, the Maillard reaction also occurs in all cells, from prokaryotes to eukaryotes, forming advanced glycation end-products (AGEs). AGEs are a heterogeneous group of compounds resulting from the irreversible reaction between biomolecules and α-dicarbonyls (α-DCs), including methylglyoxal (MGO), an unavoidable byproduct of anaerobic glycolysis and lipid peroxidation. We previously demonstrated that mutants lacking the glyoxalase enzyme displayed enhanced accumulation of α-DCs, reduced lifespan, increased neuronal damage, and touch hypersensitivity. Here, we demonstrate that mutation increased food intake and identify that MGO-derived hydroimidazolone, MG-H1, is a mediator of the observed increase in food intake. RNAseq analysis in knockdown worms identified upregulation of several neurotransmitters and feeding genes. Suppressor screening of the overfeeding phenotype identified the -tyramine- signaling as an essential pathway mediating AGE (MG-H1)-induced feeding in mutants. We also identified the GATA transcription factor as an essential upstream regulator for increased feeding upon accumulation of AGEs by partially controlling the expression of gene. Furthermore, the lack of either or receptors suppresses the reduced lifespan and rescues neuronal damage observed in mutants. Thus, in , we identified an regulated tyramine-dependent pathway mediating the toxic effects of MG-H1 AGE. Understanding this signaling pathway may help understand hedonistic overfeeding behavior observed due to modern AGE-rich diets.
• Trujillo, M. N., & Galligan, J. J. (2023). Reconsidering the role of protein glycation in disease. Nature chemical biology, 19(8), 922-927.
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  Protein glycation has long-been considered a toxic consequence of carbohydrate metabolism. Yet recent evidence demonstrates tight regulation for these non-enzymatic post-translational modifications, pointing to a broader role in cell biology rather than simply serving as a biomarker for toxicity.
• Trujillo, M. N., Jennings, E. Q., Hoffman, E. A., Zhang, H., Phoebe, A. M., Mastin, G. E., Kitamura, N., Reisz, J. A., Megill, E., Kantner, D., Marcinkiewicz, M. M., Twardy, S. M., Lebario, F., Chapman, E., McCullough, R. L., D'Alessandro, A., Snyder, N. W., Cusanovich, D. A., & Galligan, J. J. (2023). Lactoylglutathione promotes inflammatory signaling in macrophages. bioRxiv : the preprint server for biology.
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  Chronic, systemic inflammation is a pathophysiological manifestation of metabolic disorders. Inflammatory signaling leads to elevated glycolytic flux and a metabolic shift towards aerobic glycolysis and lactate generation. This rise in lactate corresponds with increased generation of lactoylLys modifications on histones, mediating transcriptional responses to inflammatory stimuli. Lactoylation is also generated through a non-enzymatic S-to-N acyltransfer from the glyoxalase cycle intermediate, lactoylglutathione (LGSH). Here, we report a regulatory role for LGSH in inflammatory signaling. In the absence of the primary LGSH hydrolase, glyoxalase 2 (GLO2), RAW264.7 macrophages display significant elevations in LGSH, while demonstrating a potentiated inflammatory response when exposed to lipopolysaccharides, corresponding with a rise in histone lactoylation. Interestingly, our data demonstrate that lactoylation is associated with more compacted chromatin than acetylation in an unstimulated state, however, upon stimulation, regions of the genome associated with lactoylation become markedly more accessible. Lastly, we demonstrate a spontaneous S-to-S acyltransfer of lactate from LGSH to CoA, yielding lactoyl-CoA. This represents the first known mechanism for the generation of this metabolite. Collectively, these data suggest that LGSH, and not intracellular lactate, is a primary contributing factor facilitating the inflammatory response.
• Dodson, M., Dai, W., Anandhan, A., Schmidlin, C. J., Liu, P., Wilson, N. C., Wei, Y., Kitamura, N., Galligan, J. J., Ooi, A., Chapman, E., & Zhang, D. D. (2022). CHML is an NRF2 target gene that regulates mTOR function. Molecular oncology, 16(8), 1714-1727.
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  The transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) is often highly expressed in non-small cell lung cancer (NSCLC). Through its target genes, NRF2 enhances cancer progression and chemo/radioresistance, leading to a poorer prognosis in patients with high NRF2 expression. In this study, we identified CHM-like Rab escort protein (CHML; encoding Rep2) as an NRF2 target gene with an antioxidant response element (ARE) in its promoter region (-1622 to -1612). Analysis of patient data curated by The Cancer Genome Atlas (TCGA) and Oncomine databases revealed that CHML mRNA expression was elevated in lung adenocarcinoma (LUAD) patient tumor tissues and correlated with decreased patient survival. Immunohistochemistry (IHC) analysis of normal versus lung cancer patient tissues revealed that Rep2 protein levels were higher in lung tumors compared with normal tissue, which also correlated with increased levels of NRF2. Importantly, siRNA-mediated knockdown of CHML/Rep2 in A549 NSCLC cells decreased their ability to proliferate. Mechanistically, Rep2 mediates mTOR function, as loss of Rep2 inhibited, whereas overexpression enhanced, mTOR translocation and activation at the lysosome. Our findings identify a novel NRF2-Rep2-dependent regulation of mTOR function.
• Farrera, D. O., & Galligan, J. J. (2022). The Human Glyoxalase Gene Family in Health and Disease. Chemical research in toxicology, 35(10), 1766-1776.
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  The glyoxalase gene family consists of six structurally and functionally diverse enzymes with broad roles in metabolism. The common feature that defines this family is based on structural motifs that coordinate divalent cations which are required for activity. These family members have been implicated in a variety of physiological processes, including amino-acid metabolism (4-hydroxyphenylpyruvate dioxygenase; ), primary metabolism (methylmalonyl-CoA epimerase; ), and aldehyde detoxication (glyoxalase 1; ) and therefore have significant associations with disease. A central function of this family is the detoxification of reactive dicarbonyls (e.g., methylglyoxal), which react with cellular nucleophiles, resulting in the modification of lipids, proteins, and DNA. These damaging modifications activate canonical stress responses such as heat shock, unfolded protein, antioxidant, and DNA damage responses. Thus, glyoxalases serve an important role in homeostasis, preventing the pathogenesis of metabolic disease states, including obesity, diabetes, cardiovascular disease, renal failure, and aging. This review presents a thorough overview of the literature surrounding this diverse enzyme class. Although extensive literature exists for some members of this family (e.g., ), little is known about the physiological role of glyoxalase domain-containing protein 4 () and 5 (), paving the way for exciting avenues for future research.
• Galligan, J. J., Johnson, M. D., & Cusanovich, D. A. (2022). Extensive evaluation of ATAC-seq protocols for native or formaldehyde-fixed nuclei. BMC Genomics.
• McGinnis, C. D., Jennings, E. Q., Harris, P. S., Galligan, J. J., & Fritz, K. S. (2022). Biochemical Mechanisms of Sirtuin-Directed Protein Acylation in Hepatic Pathologies of Mitochondrial Dysfunction. Cells, 11(13).
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  Mitochondrial protein acetylation is associated with a host of diseases including cancer, Alzheimer's, and metabolic syndrome. Deciphering the mechanisms regarding how protein acetylation contributes to disease pathologies remains difficult due to the complex diversity of pathways targeted by lysine acetylation. Specifically, protein acetylation is thought to direct feedback from metabolism, whereby nutritional status influences mitochondrial pathways including beta-oxidation, the citric acid cycle, and the electron transport chain. Acetylation provides a crucial connection between hepatic metabolism and mitochondrial function. Dysregulation of protein acetylation throughout the cell can alter mitochondrial function and is associated with numerous liver diseases, including non-alcoholic and alcoholic fatty liver disease, steatohepatitis, and hepatocellular carcinoma. This review introduces biochemical mechanisms of protein acetylation in the regulation of mitochondrial function and hepatic diseases and offers a viewpoint on the potential for targeted therapies.
• Ray, D. M., Jennings, E. Q., Maksimovic, I., Chai, X., Galligan, J. J., David, Y., & Zheng, Q. (2022). Chemical Labeling and Enrichment of Histone Glyoxal Adducts. ACS chemical biology, 17(4), 756-761.
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  Because of their long half-lives and highly nucleophilic tails, histones are particularly susceptible to accumulating nonenzymatic covalent modifications, such as glycation. The resulting modifications can have profound effects on cellular physiology due to the regulatory role histones play in all DNA-templated processes; however, the complexity of Maillard chemistry on proteins makes tracking and enriching for glycated proteins a challenging task. Here, we characterize glyoxal (GO) modifications on histones using quantitative proteomics and an aniline-derived GO-reactive probe. In addition, we leverage this chemistry to demonstrate that the glycation regulatory proteins DJ-1 and GLO1 reduce levels of histone GO adducts. Finally, we employ a two-round pull-down method to enrich histone H3 GO glycation and map these adducts to specific chromatin regions.
• Zhang, H., Rice, M. E., Alvin, J. W., Farrera-Gaffney, D., Galligan, J. J., Johnson, M. D., & Cusanovich, D. A. (2022). Extensive evaluation of ATAC-seq protocols for native or formaldehyde-fixed nuclei. BMC genomics, 23(1), 214.
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  The "Assay for Transposase Accessible Chromatin sequencing" (ATAC-seq) is an efficient and easy to implement protocol to measure chromatin accessibility that has been widely used in multiple applications studying gene regulation. While several modifications or variants of the protocol have been published since it was first described, there has not yet been an extensive evaluation of the effects of specific protocol choices head-to-head in a consistent experimental setting. In this study, we tested multiple protocol options for major ATAC-seq components (including three reaction buffers, two reaction temperatures, two enzyme sources, and the use of either native or fixed nuclei) in a well-characterized cell line. With all possible combinations of components, we created 24 experimental conditions with four replicates for each (a total of 96 samples). In addition, we tested the 12 native conditions in a primary sample type (mouse lung tissue) with two different input amounts. Through these extensive comparisons, we were able to observe the effect of different ATAC-seq conditions on data quality and to examine the utility and potential redundancy of various quality metrics.
• Jennings, E. Q., Fritz, K. S., & Galligan, J. J. (2021). Biochemical genesis of enzymatic and non-enzymatic post-translational modifications. Molecular aspects of medicine, 101053.
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  Post-translational modifications (PTMs) alter protein structure, function, and localization and play a pivotal role in physiological and pathophysiological conditions. Many PTMs arise from endogenous metabolic intermediates and serve as sensors for metabolic feedback to maintain cell growth and homeostasis. A key feature to PTMs is their biochemical genesis, which can result from either non-enzymatic adduction (nPTMs) or through enzyme-catalyzed reactions (ePTMs). The abundance and site-specificity of PTMs are determined by dedicated classes of enzymes that add (writers) or remove (erasers) the chemical addition. In this review we will highlight the biochemical genesis and regulation of a few of the 700+ PTMs that have been identified.
• Jennings, E. Q., Ray, J. D., Zerio, C. J., Trujillo, M. N., McDonald, D. M., Chapman, E., Spiegel, D. A., & Galligan, J. J. (2021). Sirtuin 2 Regulates Protein LactoylLys Modifications. Chembiochem : a European journal of chemical biology, 22(12), 2102-2106.
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  Post-translational modifications (PTMs) play roles in both physiological and pathophysiological processes through the regulation of enzyme structure and function. We recently identified a novel PTM, lactoylLys, derived through a nonenzymatic mechanism from the glycolytic by-product, lactoylglutathione. Under physiologic scenarios, glyoxalase 2 prevents the accumulation of lactoylglutathione and thus lactoylLys modifications. What dictates the site-specificity and abundance of lactoylLys PTMs, however, remains unknown. Here, we report sirtuin 2 as a lactoylLys eraser. Using chemical biology and CRISPR-Cas9, we show that SIRT2 controls the abundance of this PTM both globally and on chromatin. These results address a major gap in our understanding of how nonenzymatic PTMs are regulated and controlled.
• Khadka, S., Arthur, K., Barekatain, Y., Behr, E., Washington, M., Ackroyd, J., Crowley, K., Suriyamongkol, P., Lin, Y. H., Pham, C. D., Zielinski, R., Trujillo, M., Galligan, J., Georgiou, D. K., Asara, J., & Muller, F. (2021). Impaired anaplerosis is a major contributor to glycolysis inhibitor toxicity in glioma. Cancer & metabolism, 9(1), 27.
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  Reprogramming of metabolic pathways is crucial to satisfy the bioenergetic and biosynthetic demands and maintain the redox status of rapidly proliferating cancer cells. In tumors, the tricarboxylic acid (TCA) cycle generates biosynthetic intermediates and must be replenished (anaplerosis), mainly from pyruvate and glutamine. We recently described a novel enolase inhibitor, HEX, and its pro-drug POMHEX. Since glycolysis inhibition would deprive the cell of a key source of pyruvate, we hypothesized that enolase inhibitors might inhibit anaplerosis and synergize with other inhibitors of anaplerosis, such as the glutaminase inhibitor, CB-839.
• Marentette, J. O., Anderson, C. C., Prutton, K. M., Jennings, E. Q., Rauniyar, A. K., Galligan, J. J., & Roede, J. R. (2021). Trisomy 21 impairs PGE2 production in dermal fibroblasts. Prostaglandins & other lipid mediators, 153, 106524.
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  The triplication of human chromosome 21 results in Down syndrome (DS), the most common genetic form of intellectual disability. This aneuploid condition also results in an enhanced risk of a spectrum of comorbid conditions, such as leukemia, early onset Alzheimer's disease, and diabetes. Individuals with DS also display an increased incidence of wound healing complications and resistance to solid tumor development. Due to this unique phenotype and the involvement of eicosanoids in key comorbidities like poor healing and tumor development, we hypothesized that cells from DS individuals would display altered eicosanoid production. Using age- and sex-matched dermal fibroblasts we interrogated this hypothesis. Briefly, assessment of over 90 metabolites derived from cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome p450 systems revealed a possible deficiency in the COX system. Basal gene expression and Western blotting experiments showed significantly decreased gene expression of COX1 and 2, and COX2 protein abundance in DS fibroblasts compared to euploid controls. Further, using two different stressors, scratch wound or LPS, we found that DS fibroblasts could not upregulate COX2 abundance and prostaglandin E2 production. Together, these findings show that dermal fibroblasts from DS individuals have a deficient COX2 response, which may contribute to wound healing complications and tumor resistance in DS.
• Miller, S. R., Jilek, J. L., McGrath, M. E., Hau, R. K., Jennings, E. Q., Galligan, J. J., Wright, S. H., & Cherrington, N. J. (2021). Testicular disposition of clofarabine in rats is dependent on equilibrative nucleoside transporters. Pharmacology research & perspectives, 9(4), e00831.
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  Acute lymphoblastic leukemia (ALL) is the most common cancer in children and adolescents. Although the 5-year survival rate is high, some patients respond poorly to chemotherapy or have recurrence in locations such as the testis. The blood-testis barrier (BTB) can prevent complete eradication by limiting chemotherapeutic access and lead to testicular relapse unless a chemotherapeutic is a substrate of drug transporters present at this barrier. Equilibrative nucleoside transporter (ENT) 1 and ENT2 facilitate the movement of substrates across the BTB. Clofarabine is a nucleoside analog used to treat relapsed or refractory ALL. This study investigated the role of ENTs in the testicular disposition of clofarabine. Pharmacological inhibition of the ENTs by 6-nitrobenzylthioinosine (NBMPR) was used to determine ENT contribution to clofarabine transport in primary rat Sertoli cells, in human Sertoli cells, and across the rat BTB. The presence of NBMPR decreased clofarabine uptake by 40% in primary rat Sertoli cells (p = .0329) and by 53% in a human Sertoli cell line (p = .0899). Rats treated with 10 mg/kg intraperitoneal (IP) injection of the NBMPR prodrug, 6-nitrobenzylthioinosine 5'-monophosphate (NBMPR-P), or vehicle, followed by an intravenous (IV) bolus 10 mg/kg dose of clofarabine, showed a trend toward a lower testis concentration of clofarabine than vehicle (1.81 ± 0.59 vs. 2.65 ± 0.92 ng/mg tissue; p = .1160). This suggests that ENTs could be important for clofarabine disposition. Clofarabine may be capable of crossing the human BTB, and its potential use as a first-line treatment to avoid testicular relapse should be considered.
• Miller, S. R., Zhang, X., Hau, R. K., Jilek, J. L., Jennings, E. Q., Galligan, J. J., Foil, D. H., Zorn, K. M., Ekins, S., Wright, S. H., & Cherrington, N. J. (2021). Predicting Drug Interactions with Human Equilibrative Nucleoside Transporters 1 and 2 Using Functional Knockout Cell Lines and Bayesian Modeling. Molecular pharmacology, 99(2), 147-162.
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  Equilibrative nucleoside transporters (ENTs) 1 and 2 facilitate nucleoside transport across the blood-testis barrier (BTB). Improving drug entry into the testes with drugs that use endogenous transport pathways may lead to more effective treatments for diseases within the reproductive tract. In this study, CRISPR/CRISPR-associated protein 9 was used to generate HeLa cell lines in which ENT expression was limited to ENT1 or ENT2. We characterized uridine transport in these cell lines and generated Bayesian models to predict interactions with the ENTs. Quantification of [H]uridine uptake in the presence of the ENT-specific inhibitor -(4-nitrobenzyl)-6-thioinosine (NBMPR) demonstrated functional loss of each transporter. Nine nucleoside reverse-transcriptase inhibitors and 37 nucleoside/heterocycle analogs were evaluated to identify ENT interactions. Twenty-one compounds inhibited uridine uptake and abacavir, nevirapine, ticagrelor, and uridine triacetate had different IC values for ENT1 and ENT2. Total accumulation of four identified inhibitors was measured with and without NBMPR to determine whether there was ENT-mediated transport. Clofarabine and cladribine were ENT1 and ENT2 substrates, whereas nevirapine and lexibulin were ENT1 and ENT2 nontransported inhibitors. Bayesian models generated using Assay Central machine learning software yielded reasonably high internal validation performance (receiver operator characteristic > 0.7). ENT1 IC-based models were generated from ChEMBL; subvalidations using this training data set correctly predicted 58% of inhibitors when analyzing activity by percent uptake and 63% when using estimated-IC values. Determining drug interactions with these transporters can be useful in identifying and predicting compounds that are ENT1 and ENT2 substrates and can thereby circumvent the BTB through this transepithelial transport pathway in Sertoli cells. SIGNIFICANCE STATEMENT: This study is the first to predict drug interactions with equilibrative nucleoside transporter (ENT) 1 and ENT2 using Bayesian modeling. Novel CRISPR/CRISPR-associated protein 9 functional knockouts of ENT1 and ENT2 in HeLa S3 cells were generated and characterized. Determining drug interactions with these transporters can be useful in identifying and predicting compounds that are ENT1 and ENT2 substrates and can circumvent the blood-testis barrier through this transepithelial transport pathway in Sertoli cells.
• Galligan, J. J., Sibbersen, C., Olesen, A. S., Jorgensen, K. A., Palmfeldt, J., & Johannsen, M. (2019). Profiling of Methylglyoxal Blood Metabolism and Advanced Glycation End-Product Proteome Using a Chemical Probe. ACS Chemical Biology.
• Maksimovic, I., Zheng, Q., Trujillo, M. N., Galligan, J. J., & David, Y. (2020). An Azidoribose Probe to Track Ketoamine Adducts in Histone Ribose Glycation. Journal of the American Chemical Society, 142(22), 9999-10007.
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  Reactive cellular metabolites can modify macromolecules and form adducts known as nonenzymatic covalent modifications (NECMs). The dissection of the mechanisms, regulation, and consequences of NECMs, such as glycation, has been challenging due to the complex and often ambiguous nature of the adducts formed. Specific chemical tools are required to directly track the formation of these modifications on key targets in order to uncover their underlying physiological importance. Here, we present the novel chemoenzymatic synthesis of an active azido-modified ribose analog, 5-azidoribose (), as well as the synthesis of an inactive control derivative, 1-azidoribose (), and their application toward understanding protein ribose-glycation and . With these new probes we found that, similar to methylglyoxal (MGO) glycation, ribose glycation specifically accumulates on histones. In addition to fluorescent labeling, we demonstrate the utility of the probe in enriching modified targets, which were identified by label-free quantitative proteomics and high-resolution MS/MS workflows. Finally, we establish that the known oncoprotein and hexose deglycase, fructosamine 3-kinase (FN3K), recognizes and facilitates the removal of glycation adducts in live cells, supporting the dynamic regulation of ribose glycation as well as validating the probe as a new platform to monitor FN3K activity. Altogether, we demonstrate this probe's utilities to uncover ribose-glycation and deglycation events as well as track FN3K activity toward establishing its potential as a new cancer vulnerability.
• Nam, M. H., Smith, A. J., Pantcheva, M. B., Park, K. U., Brzezinski, J. A., Galligan, J. J., Fritz, K., Wormstone, I. M., & Nagaraj, R. H. (2020). Aspirin inhibits TGFβ2-induced epithelial to mesenchymal transition of lens epithelial cells: selective acetylation of K56 and K122 in histone H3. The Biochemical journal, 477(1), 75-97.
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  Posterior capsule opacification (PCO) is a complication after cataract surgery that can disrupt vision. The epithelial to mesenchymal transition (EMT) of lens epithelial cells (LECs) in response to transforming growth factor β2 (TGFβ2) has been considered an obligatory mechanism for PCO. In this study, we tested the efficacy of aspirin in inhibiting the TGFβ2-mediated EMT of human LECs, LECs in human lens capsular bags, and lensectomized mice. In human LECs, the levels of the EMT markers α-smooth muscle actin (α-SMA) and fibronectin were drastically reduced by treatment with 2 mM aspirin. Aspirin also halted the EMT response of TGFβ2 when introduced after EMT initiation. In human capsular bags, treatment with 2 mM aspirin significantly suppressed posterior capsule wrinkling and the expression α-SMA in capsule-adherent LECs. The inhibition of TGFβ2-mediated EMT in human LECs was not dependent on Smad phosphorylation or MAPK and AKT-mediated signaling. We found that aspirin significantly increased the acetylation of K56 and K122 in histone H3 of human LECs. Chromatin immunoprecipitation assays using acetyl-H3K56 or acetyl-H3K122 antibody revealed that aspirin blocked the TGFβ2-induced acetylation of H3K56 and H3K122 at the promoter regions of ACTA2 and COL1A1. After lensectomy in mice, we observed an increase in the proliferation and α-SMA expression of the capsule-adherent LECs, which was ameliorated by aspirin administration through drinking water. Taken together, our results showed that aspirin inhibits TGFβ2-mediated EMT of LECs, possibly from epigenetic down-regulation of EMT-related genes.
• Perer, J., Jandova, J., Fimbres, J., Jennings, E. Q., Galligan, J. J., Hua, A., & Wondrak, G. T. (2020). The sunless tanning agent dihydroxyacetone induces stress response gene expression and signaling in cultured human keratinocytes and reconstructed epidermis. Redox biology, 36, 101594.
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  Sunless (chemical) tanning is widely regarded as a safe alternative to solar UV-induced skin tanning known to be associated with epidermal genotoxic stress, but the cutaneous biology impacted by chemical tanning remains largely unexplored. Chemical tanning is based on the formation of melanin-mimetic cutaneous pigments ('melanoidins') from spontaneous amino-carbonyl ('glycation') reactions between epidermal amino acid/protein components and reactive sugars including the glycolytic ketose dihydroxyacetone (DHA). Here, we have examined the cutaneous effects of acute DHA-exposure on cultured human HaCaT keratinocytes and epidermal reconstructs, profiled by gene expression array analysis and immunodetection. In keratinocytes, DHA-exposure performed at low millimolar concentrations did not impair viability while causing a pronounced cellular stress response as obvious from rapid activation of phospho-protein signal transduction [p-p38, p-Hsp27(S15/S78), p-eIF2α] and gene expression changes (HSPA6, HMOX1, CRYAB, CCL3), not observable upon exposure to the non-ketose, tanning-inactive DHA-control glycerol. Formation of advanced glycation end products (AGEs) from posttranslational protein-adduction was confirmed by quantitative mass spectrometric detection of N-ε-(carboxyethyl)-l-lysine (CEL) and N-carboxyethyl-l-arginine, and skin cells with CRISPR-Cas9-based elimination of the carbonyl stress response gene GLO1 (encoding glyoxalase 1) displayed hypersensitivity to DHA-cytotoxicity. In human epidermal reconstructs a topical use-relevant DHA-dose regimen elicited a comparable stress response as revealed by gene expression array (HSPA1A, HSPA6, HSPD1, IL6, DDIT3, EGR1) and immunohistochemical analysis (CEL, HO-1, p-Hsp27-S78). In DHA-treated SKH-1 hairless mouse skin IHC-detection revealed epidermal occurrence of CEL- and p-Hsp27-epitopes. For comparison, stress response gene expression array analysis was performed in epidermis exposed to a supra-erythemal dose of solar simulated UV (2 MEDs), identifying genes equally or differentially sensitive to either one of these cutaneous stimuli [DHA ('sunless tanning') versus solar UV ('sun-induced tanning')]. Given the worldwide use of chemical tanners in consumer products, these prototype data documenting a DHA-induced specific cutaneous stress response deserve further molecular exploration in living human skin.
• Gaffney, D. O., Jennings, E. Q., Anderson, C. C., Marentette, J. O., Shi, T., Schou Oxvig, A. M., Streeter, M. D., Johannsen, M., Spiegel, D. A., Chapman, E., Roede, J. R., & Galligan, J. J. (2019). Non-enzymatic Lysine Lactoylation of Glycolytic Enzymes. Cell chemical biology.
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  Post-translational modifications (PTMs) regulate enzyme structure and function to expand the functional proteome. Many of these PTMs are derived from cellular metabolites and serve as feedback and feedforward mechanisms of regulation. We have identified a PTM that is derived from the glycolytic by-product, methylglyoxal. This reactive metabolite is rapidly conjugated to glutathione via glyoxalase 1, generating lactoylglutathione (LGSH). LGSH is hydrolyzed by glyoxalase 2 (GLO2), cycling glutathione and generating D-lactate. We have identified the non-enzymatic acyl transfer of the lactate moiety from LGSH to protein Lys residues, generating a "LactoylLys" modification on proteins. GLO2 knockout cells have elevated LGSH and a consequent marked increase in LactoylLys. Using an alkyne-tagged methylglyoxal analog, we show that these modifications are enriched on glycolytic enzymes and regulate glycolysis. Collectively, these data suggest a previously unexplored feedback mechanism that may serve to regulate glycolytic flux under hyperglycemic or Warburg-like conditions.
• Galligan, J. J. (2018). Chromatin Modifications in Toxicology. Chemical research in toxicology.
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  Histone modifications regulate chromatin structure and function. Primary and secondary metabolites stemming from environmental and chemical exposures may play a critical role in the underlying epigenomic state of a cell through covalent histone modifications. Future investigations should be focused on characterizing the "Histone Code" when performing toxicogenomic analyses.
• Galligan, J. J., Wepy, J. A., Streeter, M. D., Kingsley, P. J., Mitchener, M. M., Wauchope, O. R., Beavers, W. N., Rose, K. L., Wang, T., Spiegel, D. A., & Marnett, L. J. (2018). Methylglyoxal-derived posttranslational arginine modifications are abundant histone marks. Proceedings of the National Academy of Sciences of the United States of America, 115(37), 9228-9233.
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  Histone posttranslational modifications (PTMs) regulate chromatin dynamics, DNA accessibility, and transcription to expand the genetic code. Many of these PTMs are produced through cellular metabolism to offer both feedback and feedforward regulation. Herein we describe the existence of Lys and Arg modifications on histones by a glycolytic by-product, methylglyoxal (MGO). Our data demonstrate that adduction of histones by MGO is an abundant modification, present at the same order of magnitude as Arg methylation. These modifications were detected on all four core histones at critical residues involved in both nucleosome stability and reader domain binding. In addition, MGO treatment of cells lacking the major detoxifying enzyme, glyoxalase 1, results in marked disruption of H2B acetylation and ubiquitylation without affecting H2A, H3, and H4 modifications. Using RNA sequencing, we show that MGO is capable of altering gene transcription, most notably in cells lacking GLO1. Finally, we show that the deglycase DJ-1 protects histones from adduction by MGO. Collectively, our findings demonstrate the existence of a previously undetected histone modification derived from glycolysis, which may have far-reaching implications for the control of gene expression and protein transcription linked to metabolism.
• Sibbersen, C., Schou Oxvig, A. M., Bisgaard Olesen, S., Nielsen, C. B., Galligan, J. J., Jørgensen, K. A., Palmfeldt, J., & Johannsen, M. (2018). Profiling of Methylglyoxal Blood Metabolism and Advanced Glycation End-Product Proteome Using a Chemical Probe. ACS chemical biology, 13(12), 3294-3305.
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  Methylglyoxal (MG) is quantitatively the most important precursor to advanced glycation end-products (AGEs), and evidence is accumulating that it is also a causally linked to diabetes and aging related diseases. Living systems primarily reside on the glyoxalase system to detoxify MG into benign d-lactate. The flux to either glycation or detoxification, accordingly, is a key parameter for how well a system handles the ubiquitous glyoxal burden. Furthermore, insight into proteins and in particular their individual modification sites are central to understanding the involvement of MG and AGE in diabetes and aging related diseases. Here, we present a simple method to simultaneously monitor the flux of MG both to d-lactate and to protein AGE formation in a biological sample by employing an alkyne-labeled methylglyoxal probe. We apply the method to blood and plasma to demonstrate the impact of blood cell glyoxalase activity on plasma protein AGE formation. We move on to isolate proteins modified by the MG probe and accordingly can present the first general inventory of more than 100 proteins and 300 binding sites of the methylglyoxal probe on plasma as well as erythrocytic proteins. Some of the data could be validated against a number of in vivo and in vitro targets for advanced glycation previously known from the literature; the majority of proteins and specific sites however were previously unknown and may guide future research into MG and AGE to elucidate how these are functionally linked to diabetic disease and aging.
• Wauchope, O. R., Mitchener, M. M., Beavers, W. N., Galligan, J. J., Camarillo, J. M., Sanders, W. D., Kingsley, P. J., Shim, H. N., Blackwell, T., Luong, T., deCaestecker, M., Fessel, J. P., & Marnett, L. J. (2018). Oxidative stress increases M1dG, a major peroxidation-derived DNA adduct, in mitochondrial DNA. Nucleic acids research, 46(7), 3458-3467.
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  Reactive oxygen species (ROS) are formed in mitochondria during electron transport and energy generation. Elevated levels of ROS lead to increased amounts of mitochondrial DNA (mtDNA) damage. We report that levels of M1dG, a major endogenous peroxidation-derived DNA adduct, are 50-100-fold higher in mtDNA than in nuclear DNA in several different human cell lines. Treatment of cells with agents that either increase or decrease mitochondrial superoxide levels leads to increased or decreased levels of M1dG in mtDNA, respectively. Sequence analysis of adducted mtDNA suggests that M1dG residues are randomly distributed throughout the mitochondrial genome. Basal levels of M1dG in mtDNA from pulmonary microvascular endothelial cells (PMVECs) from transgenic bone morphogenetic protein receptor 2 mutant mice (BMPR2R899X) (four adducts per 106 dG) are twice as high as adduct levels in wild-type cells. A similar increase was observed in mtDNA from heterozygous null (BMPR2+/-) compared to wild-type PMVECs. Pulmonary arterial hypertension is observed in the presence of BMPR2 signaling disruptions, which are also associated with mitochondrial dysfunction and oxidant injury to endothelial tissue. Persistence of M1dG adducts in mtDNA could have implications for mutagenesis and mitochondrial gene expression, thereby contributing to the role of mitochondrial dysfunction in diseases.
• Wepy, J. A., Galligan, J. J., Kingsley, P. J., Xu, S., Goodman, M. C., Tallman, K. A., Rouzer, C. A., & Marnett, L. J. (2018). Lysophospholipases Cooperate to Mediate Lipid Homeostasis and Lysophospholipid Signaling. Journal of lipid research.
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  Lysophospholipids (LysoPL) are bioactive lipid species involved in cellular signaling processes and the regulation of cell membrane structure. LysoPLs are metabolized through the action of lysophospholipases, including lysophospholipase A1 (LYPLA1) and lysophospholipase A2 (LYPLA2). A new X-ray crystal structure of LYPLA2 compared to a previously published structure of LYPLA1 demonstrated near identical folding of the two enzymes; however, LYPLA1 and LYPLA2 have displayed distinct substrate specificities in recombinant enzyme assays. To determine how these in vitro substrate preferences translate into a relevant cellular setting and better understand the enzymes' role in LysoPL metabolism, CRISPR-Cas9 technology was utilized to generate stable knockouts of and/or in neuro2A cells. Using these cellular models in combination with a targeted lipidomics approach, LysoPL levels were quantified and compared between cell lines to determine the effect of losing lysophospholipase activity on lipid metabolism. This work suggests that LYPLA1 and LYPLA2 are each able to account for the loss of the other to maintain lipid homeostasis in cells; however, when both are deleted, LysoPL levels are dramatically increased, causing phenotypic and morphological changes to the cells.
• Beavers, W. N., Rose, K. L., Galligan, J. J., Mitchener, M. M., Rouzer, C. A., Tallman, K. A., Lamberson, C. R., Wang, X., Hill, S., Ivanova, P. T., Brown, H. A., Zhang, B., Porter, N. A., & Marnett, L. J. (2017). Protein Modification by Endogenously Generated Lipid Electrophiles: Mitochondria as the Source and Target. ACS chemical biology, 12(8), 2062-2069.
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  Determining the impact of lipid electrophile-mediated protein damage that occurs during oxidative stress requires a comprehensive analysis of electrophile targets adducted under pathophysiological conditions. Incorporation of ω-alkynyl linoleic acid into the phospholipids of macrophages prior to activation by Kdo-lipid A, followed by protein extraction, click chemistry, and streptavidin affinity capture, enabled a systems-level survey of proteins adducted by lipid electrophiles generated endogenously during the inflammatory response. Results revealed a dramatic enrichment for membrane and mitochondrial proteins as targets for adduction. A marked decrease in adduction in the presence of MitoTEMPO demonstrated a primary role for mitochondrial superoxide in electrophile generation and indicated an important role for mitochondria as both a source and target of lipid electrophiles, a finding that has not been revealed by prior studies using exogenously provided electrophiles.
• Escher, B. I., Hackermüller, J., Polte, T., Scholz, S., Aigner, A., Altenburger, R., Böhme, A., Bopp, S. K., Brack, W., Busch, W., Chadeau-Hyam, M., Covaci, A., Eisenträger, A., Galligan, J. J., Garcia-Reyero, N., Hartung, T., Hein, M., Herberth, G., Jahnke, A., , Kleinjans, J., et al. (2017). From the exposome to mechanistic understanding of chemical-induced adverse effects. Environment international, 99, 97-106.
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  The exposome encompasses an individual's exposure to exogenous chemicals, as well as endogenous chemicals that are produced or altered in response to external stressors. While the exposome concept has been established for human health, its principles can be extended to include broader ecological issues. The assessment of exposure is tightly interlinked with hazard assessment. Here, we explore if mechanistic understanding of the causal links between exposure and adverse effects on human health and the environment can be improved by integrating the exposome approach with the adverse outcome pathway (AOP) concept that structures and organizes the sequence of biological events from an initial molecular interaction of a chemical with a biological target to an adverse outcome. Complementing exposome research with the AOP concept may facilitate a mechanistic understanding of stress-induced adverse effects, examine the relative contributions from various components of the exposome, determine the primary risk drivers in complex mixtures, and promote an integrative assessment of chemical risks for both human and environmental health.
• Galligan, J. J., & Marnett, L. J. (2017). Histone Adduction and Its Functional Impact on Epigenetics. Chemical research in toxicology, 30(1), 376-387.
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  Bioactive electrophiles generated from the oxidation of endogenous and exogenous compounds are a contributing factor in numerous disease states. Their toxicity is largely attributed to the covalent modification of cellular nucleophiles, including protein and DNA. With regard to protein modification, the side-chains of Cys, His, Lys, and Arg residues are critical targets. This results in the generation of undesired protein post-translational modifications (PTMs) that can trigger dire cellular consequences. Notably, histones are Lys- and Arg-rich proteins, providing a fertile source for adduction by both exogenous and endogenous electrophiles. The regulation of histone PTMs plays a critical role in the regulation of chromatin structure and thus gene expression. This perspective focuses on the role of electrophilic protein adduction within the context of chromatin and its potential consequences on cellular law and order.
• Camarillo, J. M., Rose, K. L., Galligan, J. J., Xu, S., & Marnett, L. J. (2016). Covalent Modification of CDK2 by 4-Hydroxynonenal as a Mechanism of Inhibition of Cell Cycle Progression. Chemical research in toxicology, 29(3), 323-32.
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  Oxidative stress is a contributing factor in a number of chronic diseases, including cancer, atherosclerosis, and neurodegenerative diseases. Lipid peroxidation that occurs during periods of oxidative stress results in the formation of lipid electrophiles, which can modify a multitude of proteins in the cell. 4-Hydroxy-2-nonenal (HNE) is one of the most well-studied lipid electrophiles and has previously been shown to arrest cells at the G1/S transition. Recently, proteomic data have shown that HNE is capable of covalently modifying CDK2, the kinase responsible for the G1/S transition. Here, we identify the sites adducted by HNE using recombinant CDK2 and show that HNE treatment suppresses the kinase activity of the enzyme. We further identify sites of adduction in HNE-treated intact human colorectal carcinoma cells (RKO) and show that HNE-dependent modification in cells is long-lived, disrupts CDK2 function, and correlates with a delay of progression of the cells into S-phase. We propose that adduction of CDK2 by HNE directly alters its activity, contributing to the cell cycle delay.
• Mont, S., Davies, S. S., Roberts Second, L. J., Mernaugh, R. L., McDonald, W. H., Segal, B. H., Zackert, W., Kropski, J. A., Blackwell, T. S., Sekhar, K. R., Galligan, J. J., Massion, P. P., Marnett, L. J., Travis, E. L., & Freeman, M. L. (2016). Accumulation of isolevuglandin-modified protein in normal and fibrotic lung. Scientific reports, 6, 24919.
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  Protein lysine modification by γ-ketoaldehyde isomers derived from arachidonic acid, termed isolevuglandins (IsoLGs), is emerging as a mechanistic link between pathogenic reactive oxygen species and disease progression. However, the questions of whether covalent modification of proteins by IsoLGs are subject to genetic regulation and the identity of IsoLG-modified proteins remain unclear. Herein we show that Nrf2 and Nox2 are key regulators of IsoLG modification in pulmonary tissue and report on the identity of proteins analyzed by LC-MS following immunoaffinity purification of IsoLG-modified proteins. Gene ontology analysis revealed that proteins in numerous cellular pathways are susceptible to IsoLG modification. Although cells tolerate basal levels of modification, exceeding them induces apoptosis. We found prominent modification in a murine model of radiation-induced pulmonary fibrosis and in idiopathic pulmonary fibrosis, two diseases considered to be promoted by gene-regulated oxidant stress. Based on these results we hypothesize that IsoLG modification is a hitherto unrecognized sequelae that contributes to radiation-induced pulmonary injury and IPF.
• Shearn, C. T., Fritz, K. S., Shearn, A. H., Saba, L. M., Mercer, K. E., Engi, B., Galligan, J. J., Zimniak, P., Orlicky, D. J., Ronis, M. J., & Petersen, D. R. (2016). Deletion of GSTA4-4 results in increased mitochondrial post-translational modification of proteins by reactive aldehydes following chronic ethanol consumption in mice. Redox biology, 7, 68-77.
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  Chronic alcohol consumption induces hepatic oxidative stress resulting in production of highly reactive electrophilic α/β-unsaturated aldehydes that have the potential to modify proteins. A primary mechanism of reactive aldehyde detoxification by hepatocytes is through GSTA4-driven enzymatic conjugation with GSH. Given reports that oxidative stress initiates GSTA4 translocation to the mitochondria, we hypothesized that increased hepatocellular damage in ethanol (EtOH)-fed GSTA4(-/-) mice is due to enhanced mitochondrial protein modification by reactive aldehydes. Chronic ingestion of EtOH increased hepatic protein carbonylation in GSTA4(-/-) mice as evidenced by increased 4-HNE and MDA immunostaining in the hepatic periportal region. Using mass spectrometric analysis of biotin hydrazide conjugated carbonylated proteins, a total of 829 proteins were identified in microsomal, cytosolic and mitochondrial fractions. Of these, 417 were novel to EtOH models. Focusing on mitochondrial fractions, 1.61-fold more carbonylated proteins were identified in EtOH-fed GSTA4(-)(/-) mice compared to their respective WT mice ingesting EtOH. Bioinformatic KEGG pathway analysis of carbonylated proteins from the mitochondrial fractions revealed an increased propensity for modification of proteins regulating oxidative phosphorylation, glucose, fatty acid, glutathione and amino acid metabolic processes in GSTA4(-/-) mice. Additional analysis revealed sites of reactive aldehyde protein modification on 26 novel peptides/proteins isolated from either SV/GSTA4(-/-) PF or EtOH fed mice. Among the peptides/proteins identified, ACSL, ACOX2, MTP, and THIKB contribute to regulation of fatty acid metabolism and ARG1, ARLY, and OAT, which regulate nitrogen and ammonia metabolism having direct relevance to ethanol-induced liver injury. These data define a role for GSTA4-4 in buffering hepatic oxidative stress associated with chronic alcohol consumption and that this GST isoform plays an important role in protecting against carbonylation of mitochondrial proteins.
• Aluise, C. D., Camarillo, J. M., Shimozu, Y., Galligan, J. J., Rose, K. L., Tallman, K. A., & Marnett, L. J. (2015). Site-specific, intramolecular cross-linking of Pin1 active site residues by the lipid electrophile 4-oxo-2-nonenal. Chemical research in toxicology, 28(4), 817-27.
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  Products of oxidative damage to lipids include 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE), both of which are cytotoxic electrophiles. ONE reacts more rapidly with nucleophilic amino acid side chains, resulting in covalent protein adducts, including residue-residue cross-links. Previously, we demonstrated that peptidylprolyl cis/trans isomerase A1 (Pin1) was highly susceptible to adduction by HNE and that the catalytic cysteine (Cys113) was the preferential site of modification. Here, we show that ONE also preferentially adducts Pin1 at the catalytic Cys but results in a profoundly different modification. Results from experiments using purified Pin1 incubated with ONE revealed the principal product to be a Cys-Lys pyrrole-containing cross-link between the side chains of Cys113 and Lys117. In vitro competition assays between HNE and ONE demonstrate that ONE reacts more rapidly than HNE with Cys113. Exposure of RKO cells to alkynyl-ONE (aONE) followed by copper-mediated click chemistry and streptavidin purification revealed that Pin1 is also modified by ONE in cells. Analysis of the Pin1 crystal structure reveals that Cys113 and Lys117 are oriented toward each other in the active site, facilitating formation of an ONE cross-link.
• Kudalkar, S. N., Nikas, S. P., Kingsley, P. J., Xu, S., Galligan, J. J., Rouzer, C. A., Banerjee, S., Ji, L., Eno, M. R., Makriyannis, A., & Marnett, L. J. (2015). 13-Methylarachidonic acid is a positive allosteric modulator of endocannabinoid oxygenation by cyclooxygenase. The Journal of biological chemistry, 290(12), 7897-909.
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  Cyclooxygenase-2 (COX-2) oxygenates arachidonic acid (AA) and the endocannabinoids 2-arachidonoylglycerol (2-AG) and arachidonylethanolamide to prostaglandins, prostaglandin glyceryl esters, and prostaglandin ethanolamides, respectively. A structural homodimer, COX-2 acts as a conformational heterodimer with a catalytic and an allosteric monomer. Prior studies have demonstrated substrate-selective negative allosteric regulation of 2-AG oxygenation. Here we describe AM-8138 (13(S)-methylarachidonic acid), a substrate-selective allosteric potentiator that augments 2-AG oxygenation by up to 3.5-fold with no effect on AA oxygenation. In the crystal structure of an AM-8138·COX-2 complex, AM-8138 adopts a conformation similar to the unproductive conformation of AA in the substrate binding site. Kinetic analysis suggests that binding of AM-8138 to the allosteric monomer of COX-2 increases 2-AG oxygenation by increasing kcat and preventing inhibitory binding of 2-AG. AM-8138 restored the activity of COX-2 mutants that exhibited very poor 2-AG oxygenating activity and increased the activity of COX-1 toward 2-AG. Competition of AM-8138 for the allosteric site prevented the inhibition of COX-2-dependent 2-AG oxygenation by substrate-selective inhibitors and blocked the inhibition of AA or 2-AG oxygenation by nonselective time-dependent inhibitors. AM-8138 selectively enhanced 2-AG oxygenation in intact RAW264.7 macrophage-like cells. Thus, AM-8138 is an important new tool compound for the exploration of allosteric modulation of COX enzymes and their role in endocannabinoid metabolism.
• Wauchope, O. R., Beavers, W. N., Galligan, J. J., Mitchener, M. M., Kingsley, P. J., & Marnett, L. J. (2015). Nuclear Oxidation of a Major Peroxidation DNA Adduct, M1dG, in the Genome. Chemical research in toxicology, 28(12), 2334-42.
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  Chronic inflammation results in increased production of reactive oxygen species (ROS), which can oxidize cellular molecules including lipids and DNA. Our laboratory has shown that 3-(2-deoxy-β-d-erythro-pentofuranosyl)pyrimido[1,2-α]purin-10(3H)-one (M1dG) is the most abundant DNA adduct formed from the lipid peroxidation product, malondialdehyde, or the DNA peroxidation product, base propenal. M1dG is mutagenic in bacterial and mammalian cells and is repaired via the nucleotide excision repair system. Here, we report that M1dG levels in intact DNA were increased from basal levels of 1 adduct per 10(8) nucleotides to 2 adducts per 10(6) nucleotides following adenine propenal treatment of RKO, HEK293, or HepG2 cells. We also found that M1dG in genomic DNA was oxidized in a time-dependent fashion to a single product, 6-oxo-M1dG (to ∼ 5 adducts per 10(7) nucleotides), and that this oxidation correlated with a decline in M1dG levels. Investigations in RAW264.7 macrophages indicate the presence of high basal levels of M1dG (1 adduct per 10(6) nucleotides) and the endogenous formation of 6-oxo-M1dG. This is the first report of the production of 6-oxo-M1dG in genomic DNA in intact cells, and it has significant implications for understanding the role of inflammation in DNA damage, mutagenesis, and repair.
• Galligan, J. J., Rose, K. L., Beavers, W. N., Hill, S., Tallman, K. A., Tansey, W. P., & Marnett, L. J. (2014). Stable histone adduction by 4-oxo-2-nonenal: a potential link between oxidative stress and epigenetics. Journal of the American Chemical Society, 136(34), 11864-6.
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  Lipid electrophiles modify cellular targets, altering their function. Here, we describe histones as major targets for modification by 4-oxo-2-nonenal, resulting in a stable Lys modification structurally analogous to other histone Lys acylations. Seven adducts were identified in chromatin isolated from intact cells: four 4-ketoamides to Lys and three Michael adducts to His. A 4-ketoamide adduct residing at H3K27 was identified in stimulated macrophages. Modification of histones H3 and H4 prevented nucleosome assembly.
• Shuck, S. C., Wauchope, O. R., Rose, K. L., Kingsley, P. J., Rouzer, C. A., Shell, S. M., Sugitani, N., Chazin, W. J., Zagol-Ikapitte, I., Boutaud, O., Oates, J. A., Galligan, J. J., Beavers, W. N., & Marnett, L. J. (2014). Protein modification by adenine propenal. Chemical research in toxicology, 27(10), 1732-42.
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  Base propenals are products of the reaction of DNA with oxidants such as peroxynitrite and bleomycin. The most reactive base propenal, adenine propenal, is mutagenic in Escherichia coli and reacts with DNA to form covalent adducts; however, the reaction of adenine propenal with protein has not yet been investigated. A survey of the reaction of adenine propenal with amino acids revealed that lysine and cysteine form adducts, whereas histidine and arginine do not. N(ε)-Oxopropenyllysine, a lysine-lysine cross-link, and S-oxopropenyl cysteine are the major products. Comprehensive profiling of the reaction of adenine propenal with human serum albumin and the DNA repair protein, XPA, revealed that the only stable adduct is N(ε)-oxopropenyllysine. The most reactive sites for modification in human albumin are K190 and K351. Three sites of modification of XPA are in the DNA-binding domain, and two sites are subject to regulatory acetylation. Modification by adenine propenal dramatically reduces XPA's ability to bind to a DNA substrate.

Presentations

• Galligan, J. J., Wepy, J. A., Streeter, M. D., Kingsley, P. J., Mitchener, M. M., Wauchope, O. R., Rose, K. L., Wang, T., Spiegel, D. A., & Marnett, L. J. (2018, Spring). Methylglyoxal-derived posttranslational arginine modifications are abundant histone marks. 2018 Mountain West Society of Toxicology. Phoenix, AZ.

Reviews

• Kitamura, N., & Galligan, J. J. (2023. A global view of the human post-translational modification landscape(pp 1241-1265).
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  Post-translational modifications (PTMs) provide a rapid response to stimuli, finely tuning metabolism and gene expression and maintain homeostasis. Advances in mass spectrometry over the past two decades have significantly expanded the list of known PTMs in biology and as instrumentation continues to improve, this list will surely grow. While many PTMs have been studied in detail (e.g. phosphorylation, acetylation), the vast majority lack defined mechanisms for their regulation and impact on cell fate. In this review, we will highlight the field of PTM research as it currently stands, discussing the mechanisms that dictate site specificity, analytical methods for their detection and study, and the chemical tools that can be leveraged to define PTM regulation. In addition, we will highlight the approaches needed to discover and validate novel PTMs. Lastly, this review will provide a starting point for those interested in PTM biology, providing a comprehensive list of PTMs and what is known regarding their regulation and metabolic origins.