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. Essential for the maintenance of cellular ATP levels and carbohydrate metabolism. Required for full fertility (PubMed:18820081). Involved in response to oxidative stress by mediating plant responses to abscisic acid (ABA) and water deficits through the activation of PLDDELTA and production of phosphatidic acid (PA), a multifunctional stress signaling lipid in plants (PubMed:22589465). Associates with FBA6 to the outer mitochondrial membrane, in a redox-dependent manner, leading to binding and bundling of actin. Actin binding and bundling occurs under oxidizing conditions and is reversible under reducing conditions. May be part of a redox-dependent retrograde signal transduction network for adaptation upon oxidative stress (PubMed:23316205). Binds DNA in vitro. Together with DNA polymerase II subunit B3-1 (DPB3-1) and GAPC2, enhances heat tolerance and promotes the expression of heat-inducible genes (PubMed:32651385). D-glyceraldehyde 3-phosphate + NAD(+) + phosphate = (2R)-3-phospho-glyceroyl phosphate + H(+) + NADH Inhibition by oxidized glutathione (GSSG), S-nitrosoglutathione (GSNO), hydrogen peroxide and sodium nitroprusside (SNP). Carbohydrate degradation; glycolysis; pyruvate from D-glyceraldehyde 3-phosphate: step 1/5. Homotetramer (By similarity). Interacts with PLDDELTA (PubMed:22589465). Interacts with FBA6 and VDAC3 (PubMed:23316205). Binds to DPB3-1/NF-YC10 in response to heat-stress; this interaction promotes DPB3-1/NF-YC10 DNA-binding ability to its target promoter (PubMed:32651385). Accumulates in the nucleus under heat stress. Expressed in leaves, stems and siliques and at lower levels in roots and flowers. Not repressed by darkness or sucrose. S-glutathionylation at Cys-156 in the presence of oxidized glutathione (GSSG). S-nitrosylation in the presence of S-nitrosoglutathione (GSNO) or sodium nitroprusside (SNP). These reactions may be both a protective mechanism against irreversible oxidation and a mean to store inhibited enzyme in a recoverable form. Glutathionylation is reversed by both glutaredoxins and thioredoxins in vitro. Delayed growth, small siliques with defects in fertility, and alterations of seed and fruit development (PubMed:18820081). Reduced respiratory rates, pyruvate levels and Krebs cycle intermediates (PubMed:18820081). Increased reactive oxygen species levels (PubMed:18820081). The double mutant gapc1 gapc2 has an impaired ability to enhance heat tolerance of seedlings and to promote the expression of heat-inducible genes (PubMed:32651385). Plants contain three types of GAPDH: NAD-dependent cytosolic forms which participate in glycolysis, NAD-dependent chloroplastic forms which participate in plastidic glycolysis and NADP-dependent chloroplastic forms which participate in the photosynthetic reductive pentose phosphate pathway (Calvin-Benson cycle). All the forms are encoded by distinct genes. Belongs to the glyceraldehyde-3-phosphate dehydrogenase family.