Apolipoprotein A1 (APOA1) Active Protein

This gene encodes apolipoprotein A-I, which is the major protein component of high density lipoprotein (HDL) in plasma. The protein promotes cholesterol efflux from tissues to the liver for excretion, and it is a cofactor for lecithin cholesterolacyltransferase (LCAT) which is responsible for the formation of most plasma cholesteryl esters. This gene is closely linked with two other apolipoprotein genes on chromosome 11. Defects in this gene are associated with HDL deficiencies, including Tangier disease, and with systemic non-neuropathic amyloidosis. [provided by RefSeq, Jul 2008]

APOA1: Participates in the reverse transport of cholesterol from tissues to the liver for excretion by promoting cholesterol efflux from tissues and by acting as a cofactor for the lecithin cholesterol acyltransferase (LCAT). As part of the SPAP complex, activates spermatozoa motility. Interacts with APOA1BP and CLU. Component of a sperm activating protein complex (SPAP), consisting of APOA1, an immunoglobulin heavy chain, an immunoglobulin light chain and albumin. Interacts with NDRG1. Major protein of plasma HDL, also found in chylomicrons. Synthesized in the liver and small intestine. The oxidized form at Met-110 and Met-136 is increased in individuals with increased risk for coronary artery disease, such as in carrier of the eNOSa/b genotype and exposure to cigarette smoking. It is also present in increased levels in aortic lesions relative to native ApoA-I and increased levels are seen with increasing severity of disease. Belongs to the apolipoprotein A1/A4/E family.

Protein type: Motility/polarity/chemotaxis; Endoplasmic reticulum; Secreted, signal peptide; Secreted; Lipid-binding; Vesicle; Cell development/differentiation

Chromosomal Location of Human Ortholog: 11q23-q24

Cellular Component: extracellular space; chylomicron; cell surface; endocytic vesicle; endoplasmic reticulum lumen; early endosome; plasma membrane; extracellular region; cytoplasmic vesicle; cytosol; nucleus; vesicle

Molecular Function: identical protein binding; protein binding; enzyme binding; phospholipid transporter activity; lipase inhibitor activity; chemorepellent activity; beta-amyloid binding; cholesterol transporter activity; cholesterol binding; phospholipid binding; phosphatidylcholine binding; high-density lipoprotein binding; apolipoprotein A-I receptor binding; apolipoprotein receptor binding

Biological Process: phototransduction, visible light; negative chemotaxis; negative regulation of lipase activity; axon regeneration in the peripheral nervous system; sequestering of lipid; negative regulation of interleukin-1 beta secretion; regulation of cholesterol absorption; transforming growth factor beta receptor signaling pathway; positive regulation of stress fiber formation; response to drug; cholesterol metabolic process; platelet activation; organ regeneration; regulation of Cdc42 protein signal transduction; adrenal gland development; positive regulation of hydrolase activity; positive regulation of Rho protein signal transduction; lipoprotein metabolic process; positive regulation of transferase activity; vitamin transport; cholesterol biosynthetic process; negative regulation of cytokine secretion during immune response; cholesterol homeostasis; lipoprotein biosynthetic process; response to estrogen stimulus; peptidyl-methionine modification; phosphatidylcholine biosynthetic process; positive regulation of lipoprotein lipase activity; blood vessel endothelial cell migration; cellular lipid metabolic process; platelet degranulation; phospholipid efflux; retinoid metabolic process; transmembrane transport; response to nutrient; phospholipid homeostasis; integrin-mediated signaling pathway; receptor-mediated endocytosis; positive regulation of fatty acid biosynthetic process; regulation of protein amino acid phosphorylation; cholesterol transport; protein amino acid oxidation; protein stabilization; negative regulation of heterotypic cell-cell adhesion; neurite regeneration; cholesterol efflux; glucocorticoid metabolic process; G-protein coupled receptor protein signaling pathway; reverse cholesterol transport; negative regulation of inflammatory response; endothelial cell proliferation; blood coagulation

Disease: Hypoalphalipoproteinemia, Primary; Amyloidosis, Familial Visceral