Human Apolipoprotein A-I

This gene encodes apolipoprotein A-I, which is the major protein component of high density lipoprotein (HDL) in plasma. The encoded preproprotein is proteolytically processed to generate the mature protein, which promotes cholesterol efflux from tissues to the liver for excretion, and is a cofactor for lecithin cholesterolacyltransferase (LCAT), an enzyme 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. Alternative splicing results in multiple transcript variants, at least one of which encodes a preproprotein. [provided by RefSeq, Dec 2015]

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

Chromosomal Location of Human Ortholog: 11q23-q24

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

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

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

Disease: Amyloidosis, Familial Visceral; Hypoalphalipoproteinemia, Primary