Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH) Human Active Protein

This gene encodes a member of the glyceraldehyde-3-phosphate dehydrogenase protein family. The encoded protein has been identified as a moonlighting protein based on its ability to perform mechanistically distinct functions. The product of this gene catalyzes an important energy-yielding step in carbohydrate metabolism, the reversible oxidative phosphorylation of glyceraldehyde-3-phosphate in the presence of inorganic phosphate and nicotinamide adenine dinucleotide (NAD). The encoded protein has additionally been identified to have uracil DNA glycosylase activity in the nucleus. Also, this protein contains a peptide that has antimicrobial activity against E. coli, P. aeruginosa, and C. albicans. Studies of a similar protein in mouse have assigned a variety of additional functions including nitrosylation of nuclear proteins, the regulation of mRNA stability, and acting as a transferrin receptor on the cell surface of macrophage. Many pseudogenes similar to this locus are present in the human genome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2014]

GAPDH: a multifunctional enzyme with both glyceraldehyde-3-phosphate dehydrogenase and nitrosylase activities. A key glycolytic enzyme that catalyzes the first step of the pathway by converting D-glyceraldehyde 3-phosphate (G3P) into 3-phospho-D-glyceroyl phosphate. An important enzyme for energy metabolism, and the production of ATP and pyruvate through anaerobic glycolysis in the cytoplasm. Additionally, it participates in apoptosis, membrane trafficking, iron metabolism, nuclear activities and receptor mediated cell signaling. Its subcellular localization changes reflecting its multiple activities. Is cytosolic, but is also localized in the membrane, the nucleus, polysomes, the ER and the Golgi. Participates in transcription, RNA transport, DNA replication and apoptosis. S-nitrosylation on Cys-152 following apoptotic stimulates its interaction with SIAH2, which in turn moderates its translocation into the nucleus. Mediates cysteine S-nitrosylation of nuclear target proteins including SIRT1, HDAC2 and DNA-PK. Deregulated in lung cancer, renal cancer, breast cancer, gastric cancer, glioma, liver cancer, colorectal cancer, melanoma, prostatic cancer, pancreatic cancer and bladder cancer. Its increased expression and enzymatic activity is associated with cell proliferation and tumorigenesis, Oxidative stress impairs GAPDH catalytic activity and leads to cellular aging and apoptosis. In experimental animal models, injection of GAPDH antagonists induces apoptosis and blocks Hep3B tumor progression, suggesting a therapeutic potential of targeting GAPDH in human hepatocellular carcinoma

Protein type: Carbohydrate Metabolism - glycolysis and gluconeogenesis; EC 1.2.1.12; Oxidoreductase

Chromosomal Location of Human Ortholog: 12p13.31

Cellular Component: cytoplasm; cytosol; extracellular matrix; intracellular membrane-bound organelle; lipid particle; membrane; microtubule cytoskeleton; nuclear membrane; nucleus; plasma membrane; ribonucleoprotein complex; vesicle

Molecular Function: glyceraldehyde-3-phosphate dehydrogenase (phosphorylating) activity; identical protein binding; microtubule binding; protein binding

Biological Process: gluconeogenesis; microtubule cytoskeleton organization and biogenesis; negative regulation of translation; neuron apoptosis; protein stabilization; regulation of macroautophagy