ABCB4 (P21439) - Overview - Molecular Target Synopsis
ABCB4, Phosphatidylcholine translocator ABCB4
Enzyme Classification 184.108.40.206
Also Known as MDR3_HUMAN, ABCB4, MDR3, PGY3
Energy-dependent phospholipid efflux translocator that acts as a positive regulator of biliary lipid secretion. Functions as a floppase that translocates specifically phosphatidylcholine (PC) from the inner to the outer leaflet of the canalicular membrane bilayer into the canaliculi of hepatocytes. Translocation of PC makes the biliary phospholipids available for extraction into the canaliculi lumen by bile salt mixed micelles and therefore protects the biliary tree from the detergent activity of bile salts (PubMed:7957936, PubMed:8898203, PubMed:9366571, PubMed:17523162, PubMed:23468132, PubMed:24806754, PubMed:24723470, PubMed:24594635, PubMed:21820390). Plays a role in the recruitment of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and sphingomyelin (SM) molecules to nonraft membranes and to fu rther enrichment of SM and cholesterol in raft membranes in hepatocytes (PubMed:23468132). Required for proper phospholipid bile formation (By similarity). Indirectly involved in cholesterol efflux activity from hepatocytes into the canalicular lumen in the presence of bile salts in an ATP-dependent manner (PubMed:24045840). Promotes biliary phospholipid secretion as canaliculi-containing vesicles from the canalicular plasma membrane (PubMed:9366571, PubMed:28012258). In cooperation with ATP8B1, functions to protect hepatocytes from the deleterious detergent activity of bile salts (PubMed:21820390). Does not confer multidrug resistance. May interact with RACK1 (PubMed:19674157). Interacts with HAX1.
|Protein Length||Ensembl Gene||Ensembl Transcript||Ensembl Protein||Uniprot Isoform|
|1279||ENSG00000005471||ENST00000359206, ENST00000545634||ENSP00000352135, ENSP00000437465||P21439-2|
|1232||ENSG00000005471||ENST00000453593, ENST00000358400||ENSP00000392983, ENSP00000351172||P21439-3|
UniProt: ABCB4 is active in the following subcellular-locations: apical cell membrane, cell membrane, clathrin-coated vesicle, cytoplasm, cytoplasmic vesicle, membrane raft.
GO terms: ABCB4 is active in the following subcellular-locations: actin cytoskeleton, apical plasma membrane, clathrin-coated vesicle, cytoplasm, cytosol, extracellular exosome, focal adhesion, integral component of plasma membrane, intercellular canaliculus, membrane, membrane raft, nucleoplasm, plasma membrane.