Functions Of Glyceraldehyde-3-phosphate Dehydrogenase Research Articles

The variations in gene expression of GAPDH in Ocimum basilicum cultivars under drought-induced stress conditions.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) holds a pivotal role within the glycolytic pathway of higher plants. It has garnered attention as a significant target protein in instances of oxidative stress, where it can engage in thiolation reactions within its active site. Numerous genes encoding cytosolic iterations of GAPDH have been identified and analyzed in specific plant species. This investigation was conducted to gain insights into GAPDH's function amidst drought-induced stress. Within this framework, the basil plant (Ocimum basilicum) was chosen for focused exploration, encompassing the cloning of the comprehensive cDNA of basil GAPDH (ObGAPDH) and scrutinizing its patterns of expression. The complete sequence of Ob-GAPDH spanned 1315 base pairs. The resultant protein derived from this sequence comprised 399 amino acids, projecting a molecular weight of approximately 42.54kDa and an isoelectric point (pI) of 6.01. An examination of the evolutionary connections among various GAPDH proteins unveiled ObGAPDH's shared lineage with GAPDH proteins sourced from other plants, such as Salvia splendens and Sesamum indicum. Furthermore, computational methodologies were harnessed to predict the potential oxidative role of ObGAPDH in response to external signals. Molecular docking simulations illuminated the interaction between ObGAPDH and hydrogen peroxide (H2O2) as a ligand. Scrutinizing the expression patterns of the ObGAPDH gene under conditions of water scarcity stress brought to light diverse levels of transcriptional activity. Collectively, these findings underscore the notion that the regulation of ObGAPDH expression is contingent upon both the specific plant cultivar and the presence of stress stemming from drought conditions.

Trichoderma virens exerts herbicidal effect on Arabidopsis thaliana via modulation of amino acid metabolism

Trichoderma virens is a plant beneficial fungus well-known for its biocontrol, herbicidal and growth promotion activity. Earlier, we identified HAS (HA-synthase, a terpene cyclase) and GAPDH (glyceraldehyde-3-phosphate dehydrogenase) to be involved in the production of multiple non-volatiles and non-volatile+volatile metabolites, respectively. The present study delineates the function of HAS and GAPDH in regulating herbicidal activity, using the model plant Arabidopsis thaliana. Under axenic conditions, rosette-biomass of seedlings co-cultivated with ΔHAS (HASR) and ΔGAPDH (GAPDHR) was higher than WT-Trichoderma (WTR) as well as non-colonized control (NoTR), even though the root colonization ability was reduced. However, HASR biomass was still higher than those of GAPDHR, indicating that blocking volatiles will not provide any additional contribution over non-volatile metabolites for Trichoderma-induced herbicidal activity. LC-MS analysis revealed that loss of herbicidal activity of ΔHAS/ΔGAPDH was associated with an increase in the levels of amino acids, which coincided with reduced expression levels of amino-acid catabolism and anabolism related genes in HASR/GAPDHR. RNAi-mediated suppression of an oxidoreductase gene, VDN5, specifically prevented viridin-to-viridiol conversion. Additionally, vdn5 mimics ΔHAS, in terms of amino-acid metabolism gene expression and partially abolishes the herbicidal property of WT-Trichoderma. Thus, the study provides mechanistic frame-work for better utilization of Trichoderma virens for biocontrol purposes, balancing between plant growth promotion and herbicidal activity.

The uncommon function and mechanism of the common enzyme glyceraldehyde-3-phosphate dehydrogenase in the metamorphosis of Helicoverpa armigera.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a key enzyme in glycolysis, is commonly used as an internal reference gene in humans, mice, and insects. However, the function of GAPDH in insect development, especially in metamorphosis, has not been reported. In the present study, Helicoverpa armigera and Spodoptera frugiperda ovarian cell lines (Sf9 cells) were used as materials to study the function and molecular mechanism of GAPDH in larval metamorphosis. The results showed that HaGAPDH was more closely related to GAPDH of S. frugiperda and Spodoptera litura. The transcript peaks of HaGAPDH in sixth instar larvae were 6L-3 (epidermal and midgut) and 6L-1 (fat body) days, and 20E and methoprene significantly upregulated the transcripts of HaGAPDH of larvae in qRT-PCR. HaGAPDH-GFP-His was specifically localized in mitochondria in Sf9 cells. Knockdown of HaGAPDH by RNA interference (RNAi) in sixth instar larvae resulted in weight loss, increased mortality, and decreases in the pupation rate and emergence rates. HaGAPDH is directly bound to soluble trehalase (HaTreh1) physically and under 20E treatment in yeast two-hybrid, coimmunoprecipitation, and colocalization experiments. In addition, knockdown of HaGAPDH increased the Treh1 activity, which in turn decreased the trehalose content but increased the glucose content in larvae. Therefore, these data demonstrated that GAPDH controlled the glucose content within the normal range to ensure glucose metabolism and metamorphosis by directly binding with HaTreh1.

GAPDH in neuroblastoma: Functions in metabolism and survival.

Neuroblastoma is a pediatric cancer of neural crest cells. It develops most frequently in nerve cells around the adrenal gland, although other locations are possible. Neuroblastomas rely on glycolysis as a source of energy and metabolites, and the enzymes that catalyze glycolysis are potential therapeutic targets for neuroblastoma. Furthermore, glycolysis provides a protective function against DNA damage, and there is evidence that glycolysis inhibitors may improve outcomes from other cancer treatments. This mini-review will focus on glyceraldehyde 3-phosphate dehydrogenase (GAPDH), one of the central enzymes in glycolysis. GAPDH has a key role in metabolism, catalyzing the sixth step in glycolysis and generating NADH. GAPDH also has a surprisingly diverse number of localizations, including the nucleus, where it performs multiple functions, and the plasma membrane. One membrane-associated function of GAPDH is stimulating glucose uptake, consistent with a role for GAPDH in energy and metabolite production. The plasma membrane localization of GAPDH and its role in glucose uptake have been verified in neuroblastoma. Membrane-associated GAPDH also participates in iron uptake, although this has not been tested in neuroblastoma. Finally, GAPDH activates autophagy through a nuclear complex with Sirtuin. This review will discuss these activities and their potential role in cancer metabolism, treatment and drug resistance.

Glyceraldehyde-3-phosphate dehydrogenase present in extracellular vesicles from Leishmania major suppresses host TNF-alpha expression

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) fulfills various physiological roles that are unrelated to its glycolytic function. However, to date, the nonglycolytic function of GAPDH in trypanosomal parasites is absent from the literature. Exosomes secreted from Leishmania, like entire parasites, were found to have a significant impact on macrophage cell signaling and function, indicating cross talk with the host immune system. In this study, we demonstrate that the Leishmania GAPDH (LmGAPDH) protein is highly enriched within the extracellular vesicles (EVs) secreted during infection. To understand the function of LmGAPDH in EVs, we generated control, overexpressed, half-knockout (HKO), and complement cell lines. HKO cells displayed lower virulence compared with control cells when macrophages and BALB/c mice were infected with them, implying a crucial role for LmGAPDH in Leishmania infection and disease progression. Furthermore, upon infection of macrophages with HKO mutant Leishmania and its EVs, despite no differences in TNFA mRNA expression, there was a considerable increase in TNF-α protein expression compared with control, overexpressed, and complement parasites as determined by ELISA, RT-PCR, and immunoblot data. In vitro protein translation studies suggest that LmGAPDH-mediated TNF-α suppression occurs in a concentration-dependent manner. Moreover, mRNA binding assays also verified that LmGAPDH binds to the AU-rich 3′-UTR region of TNFA mRNA, limiting its production. Together, these findings confirmed that the LmGAPDH contained in EVs inhibits TNF-α expression in macrophages during infection via posttranscriptional repression.

Characteristics and functions of glyceraldehyde 3-phosphate dehydrogenase S-nitrosylation during controlled aging of elm and Arabidopsis seeds.

Seed aging is the gradual decline in seed vigor, during which programmed cell death (PCD) occurs. The functions of nitric oxide (NO) are exerted through protein S-nitrosylation, a reversible post-translational modification. During seed aging, more than 80 proteins are S-nitrosylated, but the particular role of individual proteins is unknown. Here, we showed that the S-nitrosylation level of glyceraldehyde 3-phosphate dehydrogenase (UpGAPDH) in elm (Ulmus pumila L.) seeds increased after controlled deterioration treatment. UpGAPDH was S-nitrosylated at Cys154 during S-nitrosoglutathione (GSNO) treatment, and its oligomerization was triggered both in vitro and in elm seeds. Interestingly, UpGAPDH interacted with the mitochondrial voltage-dependent anion channel in an S-nitrosylation-dependent way. Some UpGAPDH-green fluorescent protein in Arabidopsis protoplasts co-localized with mitochondria during the GSNO treatment, while the S-nitrosylation-defective UpGAPDH C154S-GFP protein did not. Seeds of oxUpGAPDH lines showed cell death and lost seed vigor rapidly during controlled deterioration treatment-triggered seed aging, while those overexpressing S-nitrosylation-defective UpGAPDH-Cys154 did not. Our results suggest that S-nitrosylation of UpGAPDH may accelerate cell death and seed deterioration during controlled deterioration treatment. These results provide new insights into the effects of UpGAPDH S-nitrosylation on protein interactions and seed aging.

Antitumor Activity of Asperphenin B by Induction of Apoptosis and Regulation of Glyceraldehyde-3-phosphate Dehydrogenase in Human Colorectal Cancer Cells.

Colorectal cancer (CRC) is a common and intractable malignancy with a high mortality risk. Conventional chemotherapeutics are effective for patients with early stage CRC, but the majority of deaths of CRC patients are linked to acquired drug resistance or metastasis occurrence. Asperphenin B (1), a lipopeptidyl benzophenone isolated from a marine-derived Aspergillus sp. fungus, reportedly possesses antiproliferative activity against cancer cells. However, its antitumor activity and the underlying molecular mechanisms remain unexplored. In this study, 1 induced G2/M phase cell cycle arrest and subsequent apoptotic cell death and inhibited tumor growth in a xenograft model. The 1-induced G2/M phase arrest was associated with the regulation of checkpoint proteins, including Chk1/2 and Cdc25c. The 1-induced apoptosis was correlated with an upregulation of p53 and cleaved caspases and a downregulation of survivin. Further experiments revealed that 1-mediated suppression of migration and invasion of metastatic HCT116 cells was partially associated with the downregulation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression. The antimetastatic potential of 1 was also confirmed by E-cadherin upregulation and N-cadherin and Snail downregulation, which were in turn associated with the GAPDH regulation. These findings highlight the potential use of 1 as a novel candidate for treating metastatic CRC with the modulation of GAPDH function.

Chlamydia trachomatis glyceraldehyde 3-phosphate dehydrogenase: Enzyme kinetics, high-resolution crystal structure, and plasminogen binding.

Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is an evolutionarily conserved essential enzyme in the glycolytic pathway. GAPDH is also involved in a wide spectrum of non-catalytic cellular 'moonlighting' functions. Bacterial surface-associated GAPDHs engage in many host interactions that aid in colonization, pathogenesis, and virulence. We have structurally and functionally characterized the recombinant GAPDH of the obligate intracellular bacteria Chlamydia trachomatis, the leading cause of sexually transmitted bacterial and ocular infections. Contrary to earlier speculations, recent data confirm the presence of glucose-catabolizing enzymes including GAPDH in both stages of the biphasic life cycle of the bacterium. The high-resolution crystal structure described here provides a close-up view of the enzyme's active site and surface topology and reveals two chemically modified cysteine residues. Moreover, we show for the first time that purified C. trachomatis GAPDH binds to human plasminogen and plasmin. Based on the versatility of GAPDH's functions, data presented here emphasize the need for investigating the Chlamydiae GAPDH's involvement in biological functions beyond energy metabolism.

Identification of Bacterial Protein Interaction Partners Points to New Intracellular Functions of Francisella tularensis Glyceraldehyde-3-Phosphate Dehydrogenase.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is well known for its involvement in numerous non-metabolic processes inside mammalian cells. Alternative functions of prokaryotic GAPDH are mainly deduced from its extracellular localization ability to bind to selected host proteins. Data on its participation in intracellular bacterial processes are scarce as there has been to date only one study dealing with this issue. We previously have reported several points of evidence that the GAPDH homolog of Francisella tularensis GapA might also exert additional non-enzymatic functions. Following on from our earlier observations we decided to identify GapA’s interacting partners within the bacterial proteome to explore its new roles at intracellular level. The quantitative proteomics approach based on stable isotope labeling of amino acids in cell culture (SILAC) in combination with affinity purification mass spectrometry enabled us to identify 18 proteins potentially interacting with GapA. Six of those interactions were further confirmed by alternative methods. Half of the identified proteins were involved in non-metabolic processes. Further analysis together with quantitative label-free comparative analysis of proteomes isolated from the wild-type strain strain with deleted gapA gene suggests that GapA is implicated in DNA repair processes. Absence of GapA promotes secretion of its most potent interaction partner the hypothetical protein with peptidase propeptide domain (PepSY) thereby indicating that it impacts on subcellular distribution of some proteins.

Src-mediated phosphorylation of GAPDH regulates its nuclear localization and cellular response to DNA damage.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key enzyme involved in energy metabolism. Recently, GAPDH has been suggested to have extraglycolytic functions in DNA repair, but the underlying mechanism for the GAPDH response to DNA damage remains unclear. Here, we demonstrate that the tyrosine kinase Src is activated under DNA damage stress and phosphorylates GAPDH at Tyr41. This phosphorylation of GAPDH is essential for its nuclear translocation and DNA repair function. Blocking the nuclear import of GAPDH by suppressing Src signaling or through a GAPDH Tyr41 mutation impairs its response to DNA damage. Nuclear GAPDH is recruited to DNA lesions and associates with DNA polymerase β (Pol β) to function in DNA repair. Nuclear GAPDH promotes Pol β polymerase activity and increases base excision repair (BER) efficiency. Furthermore, GAPDH knockdown dramatically decreases BER efficiency and sensitizes cells to DNA damaging agents. Importantly, the knockdown of GAPDH in colon cancer SW480 cells and xenograft models effectively enhances their sensitivity to the chemotherapeutic drug 5-FU. In summary, our findings provide mechanistic insight into the new function of GAPDH in DNA repair and suggest a potential therapeutic target in chemotherapy.

Influence of Oxidative Stress on Catalytic and Non-glycolytic Functions of Glyceraldehyde-3-phosphate Dehydrogenase.

Glyceraldehyde-3-phosphate Dehydrogenase (GAPDH) is a unique enzyme that, besides its main function in glycolysis (catalysis of glyceraldehyde-3-phosphate oxidation), possesses a number of non-glycolytic activities. The present review summarizes information on the role of oxidative stress in the regulation of the enzymatic activity as well as non-glycolytic functions of GAPDH. Based on the analysis of literature data and the results obtained in our research group, mechanisms of the regulation of GAPDH functions through the oxidation of the sulfhydryl groups in the active site of the enzyme have been suggested. Mechanism of GAPDH oxidation includes consecutive oxidation of the catalytic Cysteine (Cys150) into sulfenic, sulfinic, and sulfonic acid derivatives, resulting in the complete inactivation of the enzyme. The cysteine sulfenic acid reacts with reduced glutathione (GSH) to form a mixed disulfide (S-glutathionylated GAPDH) that further reacts with Cys154 yielding the disulfide bond in the active site of the enzyme. In contrast to the sulfinic and sulfonic acids, the mixed disulfide and the intramolecular disulfide bond are reversible oxidation products that can be reduced in the presence of GSH or thioredoxin. Oxidation of sulfhydryl groups in the active site of GAPDH is unavoidable due to the enhanced reactivity of Cys150. The irreversible oxidation of Cys150 is prevented by Sglutathionylation and disulfide bonding with Cys154. The oxidation/reduction of the sulfhydryl groups in the active site of GAPDH can be used for regulation of glycolysis and numerous side activities of this enzyme including the induction of apoptosis.

A ‘sweet spot’ for complement receptor CD46 activity via direct regulation of glycolytic vs. moonlighting functions of GAPDH

Abstract Autocrine engagement of the complement receptor CD46, driven by T cell receptor (TCR) activation on human CD4+ T cells, is critical for human Th1 induction: Processing of the intracellular CD46 domains by γ-secretase and their nuclear translocation mediates the expression of nutrient transporters GLUT1 and LAT1, increases glycolysis and oxidative phosphorylation, and enables metabolic reprogramming required for cell growth, expansion and effector function. How, at the molecular level, CYT-1 enables this fundamental cellular adaptation remains unknown. To probe for CYT-1 interacting proteins we generated antibodies against cleaved CYT-1 and performed co-immunoprecipitation experiments. Unexpectedly, mass spectrometry revealed association of CYT-1 with several glycolytic enzymes, including glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Although ELISA and MST-based experiments confirmed a strong, dose-dependent CYT-1/GAPDH interaction, glycolytic activity was hardly affected by CYT-1. Rather, CYT-1 modulated the activity of a key ‘moonlighting function’ of GAPDH, namely the posttranscriptional regulation of mRNA stability/translation: CYT-1 binding fostered desoligomerization of glycolytically active GAPDH tetramers to monomers with altered mRNA binding abilities – particularly for mRNAs encoding metabolic enzymes. These data identify CD46 as a ‘shape-shifter’ of GAPDH activity, critically balancing its canonical (glycolysis) versus non-canonical (posttranscriptional regulation) activity – further substantiating the notion that autocrine complement is a critical regulator of normal cell physiology.

Regulation of Autophagy by Nuclear GAPDH and Its Aggregates in Cancer and Neurodegenerative Disorders.

Several studies indicate that the cytosolic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has pleiotropic functions independent of its canonical role in glycolysis. The GAPDH functional diversity is mainly due to post-translational modifications in different amino acid residues or due to protein–protein interactions altering its localization from cytosol to nucleus, mitochondria or extracellular microenvironment. Non-glycolytic functions of GAPDH include the regulation of cell death, autophagy, DNA repair and RNA export, and they are observed in physiological and pathological conditions as cancer and neurodegenerative disorders. In disease, the knowledge of the mechanisms regarding GAPDH-mediated cell death is becoming fundamental for the identification of novel therapies. Here, we elucidate the correlation between autophagy and GAPDH in cancer, describing the molecular mechanisms involved and its impact in cancer development. Since autophagy is a degradative pathway associated with the regulation of cell death, we discuss recent evidence supporting GAPDH as a therapeutic target for autophagy regulation in cancer therapy. Furthermore, we summarize the molecular mechanisms and the cellular effects of GAPDH aggregates, which are correlated with mitochondrial malfunctions and can be considered a potential therapeutic target for various diseases, including cancer and neurodegenerative disorders.

Regulation of endothelial cell survival and death by the MAP kinase/ERK kinase kinase 3 - glyceraldehyde-3-phosphate dehydrogenase signaling axis

Endothelial cell injury and death precede atherosclerosis development. Thus, it is important to understand the mechanisms that lead to these early changes in endothelial cells. Although members of the MAP kinase/ERK kinase (MEK) kinase 3 (MEKK3)-MEK5-ERK5 module play an essential role in underpinning endothelial cell survival, how they execute these actions remain poorly understood. Furthermore, there is poor understanding of death-inducing pathways in endothelial cells and it is also unclear whether there are direct interactions between the kinase module and death-inducing pathways. Using immunoprecipitation and liquid chromatography-electrospray ionisation tandem mass spectrometry approaches, we show in human umbilical vein endothelial cells that the MEKK3-MEK5-ERK5 ternary complex contains glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a glycolytic enzyme that can trigger the death of certain cell-types. GAPDH binds directly to MEKK3. Interestingly, serum depletion, a trigger of endothelial cell death, results in a rapid loss of cytosolic MEKK3 and MEKK3-GAPDH interaction. MEKK3 rapidly reappears in the cytosol upon serum replenishment, accompanied by the restoration of MEKK3-GAPDH interaction. During serum starvation or exposure to cytotoxic concentrations of H2O2, GAPDH accumulates in the nucleus. Inhibition of the nuclear accumulation of GAPDH with R-(−)-deprenyl hydrochloride attenuates the degree of cell death. Serum replenishment of serum-starved cells reduces the level of nuclear GAPDH and prevents cell death. Cell-free assays show phosphorylation of GAPDH on four residues by MEKK3. These data not only strongly implicate nuclear GAPDH in causing endothelial cell death but also reveal a potential mechanism for MEKK3 to regulate GAPDH function and hence promote endothelial cell survival.

Pleiotropic effects of moonlighting glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in cancer progression, invasiveness, and metastases.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) may represent the quintessential example of a moonlighting protein. The latter are a new, intriguing class of cell proteins which exhibit multiple activities in different subcellular locales apart from their initially, well-characterized function. As such, apart from its classical role in energy production, membrane-bound GAPDH is required for membrane fusion, endocytosis and, intriguingly, for iron transport. Cytoplasmic GAPDH regulates mRNA stability and is required for ER to Golgi trafficking. Nuclear GAPDH is involved in apoptosis, transcriptional gene regulation, the maintenance of DNA integrity, as well as nuclear tRNA export. Paradoxically, the etiology of a number of human pathologies is dependent upon GAPDH structure and function. In particular, recent evidence indicates a significant role for moonlighting GAPDH in tumorigenesis. Specifically, these include its role in the survival of tumor cells, in tumor angiogenesis, as well as its control of tumor cell gene expression and posttranscriptional regulation of tumor cell mRNA. Each of these activities correlates with increased tumor progression and, unfortunately, a poor prognosis for the afflicted individual.

Nicotinamide adenine dinucleotide (NAD) oxidation preserves T cell function under lactic acidosis characteristic of the tumor microenvironment (TME)

Abstract Cancers are adept at employing metabolic events to evade host immunity. The TME is often glucose depleted and enriched with lactic acid, weakening effector T cell (Teff) function and interferon (IFN)-γ production. By contrast, immunosuppressive T-regulatory (Treg) cells are well adapted to low glucose and elevated lactate and enriched in the TME. Overcoming immunosuppressive metabolic conditions in the TME may be an important step towards improving anti-tumor immunotherapy. Here we show that NAD oxidation can protect Teffs from the immunosuppressive effects of lactic acid. We found that Teff proliferation and IFN-γ production can be controlled through NAD redox metabolism and NAD-dependent enzymes, including glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Metabolomic and bioenergetics studies showed that reducing NAD led to accumulation of pre-GAPDH glycolytic metabolites and impaired glycolytic flux similar to GAPDH inhibition, which was reversed by NAD oxidation. Human and murine Teffs exposed to lactate, oligomycin, rotenone, or antimycin lost GAPDH function despite sufficient glucose, limiting glycolysis and IFN-γ mRNA translation, while the Treg transcription factor Foxp3 was stabilized. Oxidizing NAD (pyruvate, mitochondrial uncoupling, β-lapachone, α-ketobutyrate) rescued Teff glycolysis and restored their function despite ambient lactate, while Foxp3 turnover increased in a poly-(ADP-ribose) polymerase dependent manner, using NAD as substrate. Our results identify a novel therapeutic approach to overcoming metabolic barriers to anti-tumor immunity, and provide new mechanistic insights into the role of NAD redox metabolism in controlling T cell function in the TME.

PRMT1 negatively regulates activation-induced cell death in macrophages by arginine methylation of GAPDH

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is implicated in cell death in addition to a role as a glycolytic enzyme. In particular, when cells are exposed to cellular stressors involving nitric oxide (NO) production, GAPDH can undergo NO-induced S-nitrosylation and S-nitrosylated GAPDH has been shown to elicit apoptosis. However, the mechanism underlying the regulation of the pro-apoptotic function of GAPDH remains unclear. Here, we found that protein arginine methyltransferase 1 (PRMT1) mediated arginine methylation of GAPDH in primary bone marrow-derived macrophages in a NO-dependent manner. Moreover, PRMT1 inhibited S-nitrosylation of GAPDH as well as its binding to SIAH1, thereby reducing the nuclear translocation of GAPDH in lipopolysaccharide (LPS)/interferon (IFN)-γ-activated macrophages. Furthermore, depletion of PRMT1 expression by RNA interference potentiated LPS/IFN-γ-induced apoptosis in macrophages. Taken together, our results suggest that PRMT1 has a previously unrecognized function to inhibit activation-induced cell death of macrophages through arginine methylation of GAPDH.

Cytosolic glyceraldehyde-3-phosphate dehydrogenases play crucial roles in controlling cold-induced sweetening and apical dominance of potato (Solanum tuberosum L.) tubers.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an important enzyme that functions in producing energy and supplying intermediates for cellular metabolism. Recent researches indicate that GAPDHs have multiple functions beside glycolysis. However, little information is available for functions of GAPDHs in potato. Here, we identified 4 putative cytosolic GAPDH genes in potato genome and demonstrated that the StGAPC1, StGAPC2, and StGAPC3, which are constitutively expressed in potato tissues and cold inducible in tubers, encode active cytosolic GAPDHs. Cosuppression of these 3 GAPC genes resulted in low tuber GAPDH activity, consequently the accumulation of reducing sugars in cold stored tubers by altering the tuber metabolite pool sizes favoring the sucrose pathway. Furthermore, GAPCs-silenced tubers exhibited a loss of apical dominance dependent on cell death of tuber apical bud meristem (TAB-meristem). It was also confirmed that StGAPC1, StGAPC2, and StGAPC3 interacted with the autophagy-related protein 3 (ATG3), implying that the occurrence of cell death in TAB-meristem could be induced by ATG3 associated events. Collectively, the present research evidences first that the GAPC genes play crucial roles in diverse physiological and developmental processes in potato tubers.

Rice NAD+-dependent histone deacetylase OsSRT1 represses glycolysis and regulates the moonlighting function of GAPDH as a transcriptional activator of glycolytic genes

Sirtuins, a family of proteins with homology to the yeast silent information regulator 2 (Sir2), are NAD+-dependent histone deacetylases and play crucial roles in energy sensing and regulation in yeast and animal cells. Plants are autotrophic organisms and display distinct features of carbon and energy metabolism. It remains largely unexplored whether and how plant cells sense energy/redox status to control carbon metabolic flux under various growth conditions. In this work, we show that the rice nuclear sirtuin OsSRT1 not only functions as an epigenetic regulator to repress glycolytic genes expression and glycolysis in seedlings, but also inhibits transcriptional activity of glyceraldehyde-3-phosphatedehydrogenase (GAPDH) that is enriched on glycolytic genes promoters and stimulates their expression. We show that OsSRT1 reduces GAPDH lysine acetylation and nuclear accumulation that are enhanced by oxidative stress. Mass spectrometry identified six acetylated lysines regulated by OsSRT1. OsSRT1-dependent lysine deacetylation of OsGAPDH1 represses transcriptional activity of the protein. The results indicate that OsSRT1 represses glycolysis by both regulating epigenetic modification of histone and inhibiting the moonlighting function of GAPDH as a transcriptional activator of glycolytic genes in rice.

Role of Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH) in DNA Repair.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is widely known as a glycolytic enzyme. Nevertheless, various functions of GAPDH have been found that are unrelated to glycolysis. Some of these functions presume interaction of GAPDH with DNA, but the mechanism of its translocation to the nucleus is not fully understood. When in the nucleus, GAPDH participates in the initiation of apoptosis and transcription of genes involved in antiapoptotic pathways and cell proliferation and plays a role in the regulation of telomere length. Several authors have shown that GAPDH displays the uracil-DNA glycosylase activity and interacts with some types of DNA damages, such as apurinic/apyrimidinic sites, nucleotide analogs, and covalent DNA adducts with alkylating agents. Moreover, GAPDH can interact with proteins participating in DNA repair, such as APE1, PARP1, HMGB1, and HMGB2. In this review, the functions of GAPDH associated with DNA repair are discussed in detail.