Has both glyceraldehyde-3-phosphate dehydrogenase and nitrosylase activities, thereby playing a role in glycolysis and nuclear functions, respectively. Glyceraldehyde-3-phosphate dehydrogenase is a key enzyme in glycolysis that catalyzes the first step of the pathway by converting D-glyceraldehyde 3-phosphate (G3P) into 3-phospho-D-glyceroyl phosphate (By similarity). Modulates the organization and assembly of the cytoskeleton. Facilitates the CHP1-dependent microtubule and membrane associations through its ability to stimulate the binding of CHP1 to microtubules (By similarity). Component of the GAIT (gamma interferon-activated inhibitor of translation) complex which mediates interferon-gamma-induced transcript-selective translation inhibition in inflammation processes. Upon interferon-gamma treatment assembles into the GAIT complex which binds to stem loop-containing GAIT elements in the 3'-UTR of diverse inflammatory mRNAs (such as ceruplasmin) and suppresses their translation. Also plays a role in innate immunity by promoting TNF-induced NF-kappa-B activation and type I interferon production, via interaction with TRAF2 and TRAF3, respectively (By similarity). Participates in nuclear events including transcription, RNA transport, DNA replication and apoptosis. Nuclear functions are probably due to the nitrosylase activity that mediates cysteine S-nitrosylation of nuclear target proteins such as SIRT1, HDAC2 and PRKDC (By similarity). D-glyceraldehyde 3-phosphate + NAD(+) + phosphate = (2R)-3-phospho-glyceroyl phosphate + H(+) + NADH L-cysteinyl-[protein] + S-nitroso-L-cysteinyl-[GAPDH] = L-cysteinyl-[GAPDH] + S-nitroso-L-cysteinyl-[protein] Glyceraldehyde-3-phosphate dehydrogenase activity is inhibited by fumarate, via the formation of S-(2-succinyl)cysteine residues. Carbohydrate degradation; glycolysis; pyruvate from D-glyceraldehyde 3-phosphate: step 1/5. Homotetramer (By similarity). Interacts with TPPP; the interaction is direct (By similarity). Interacts (when S-nitrosylated) with SIAH1; leading to nuclear translocation. Interacts with RILPL1/GOSPEL, leading to prevent the interaction between GAPDH and SIAH1 and prevent nuclear translocation. Interacts with CHP1; the interaction increases the binding of CHP1 with microtubules. Associates with microtubules (By similarity). Interacts with EIF1AD, USP25, PRKCI and WARS1. Interacts with phosphorylated RPL13A; inhibited by oxidatively-modified low-densitity lipoprotein (LDL(ox)). Component of the GAIT complex. Interacts with FKBP6; leading to inhibit GAPDH catalytic activity. Interacts with TRAF2, promoting TRAF2 ubiquitination. Interacts with TRAF3, promoting TRAF3 ubiquitination (By similarity). Translocates to the nucleus following S-nitrosylation and interaction with SIAH1, which contains a nuclear localization signal. Colocalizes with CHP1 to small punctate structures along the microtubules tracks. The [IL]-x-C-x-x-[DE] motif is a proposed target motif for cysteine S-nitrosylation mediated by the iNOS-S100A8/A9 transnitrosylase complex. ISGylated. S-nitrosylation leads to interaction with SIAH1, followed by translocation to the nucleus. S-nitrosylation is induced by interferon-gamma and LDL(ox) implicating the iNOS-S100A8/9 transnitrosylase complex and seems to prevent interaction with phosphorylated RPL13A and to interfere with GAIT complex activity (By similarity). Sulfhydration increases catalytic activity. Oxidative stress can promote the formation of high molecular weight disulfide-linked GAPDH aggregates, through a process called nucleocytoplasmic coagulation. Belongs to the glyceraldehyde-3-phosphate dehydrogenase family.