Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a tetramer containing identical chains. It catalyzes the reversible oxidative phosphorylation of glyceraldehyde-phosphate, which is a critical energy-yielding step in carbohydrate metabolism. It binds to several proteins including actin, tubulin, amyloid precursor, polyglutamine peptides, DRPLA (dentatorubral-pallidoluysian atrophy), and huntingtin. Protein kinase Cι/λbinds and phosphorylates GAPDH. Phosphorylated GAPDH associates with cytoskeletal elements and controls microtubule dynamics in the early secretory pathway. Poly(ADP-ribose) polymerase-1 (PARP1) interacts with GAPDH and thereby mediates brain damage in the presence of oxidative/nitrosative stress. GAPDH forms a part of OCA-S, the multicomponent OCT1 (octamer-motif-binding factor) coactivator complex, which is involved in the S phase-dependent histone H2B transcription. This association is responsible for linking H2B transcriptional machinery to cell cycle regulation and to the cellular metabolic state. GAPDH is also a component of the functional GAIT (interferon-γ-activated inhibitor of translation) mRNP (messenger ribonucleoprotein). GAPDH expression is dysregulated during melanoma progression.
