Recombinant Human Multidrug resistance protein 3 (ABCB4), Truncated

Uniprot Id

P21439

Target Species

Human

Target Name

ABCB4

Target Full Name

Phosphatidylcholine translocator ABCB4

Target Function

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. Plays a role in the recruitment of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and sphingomyelin (SM) molecules to nonraft membranes and to further enrichment of SM and cholesterol in raft membranes in hepatocytes. Required for proper phospholipid bile formation. Indirectly involved in cholesterol efflux activity from hepatocytes into the canalicular lumen in the presence of bile salts in an ATP-dependent manner. Promotes biliary phospholipid secretion as canaliculi-containing vesicles from the canalicular plasma membrane. In cooperation with ATP8B1, functions to protect hepatocytes from the deleterious detergent activity of bile salts. Does not confer multidrug resistance.

Target Involvement

Cholestasis, progressive familial intrahepatic, 3 (PFIC3); Cholestasis of pregnancy, intrahepatic 3 (ICP3); Gallbladder disease 1 (GBD1)

Target Subcellular Location

Cell membrane; Multi-pass membrane protein. Apical cell membrane; Multi-pass membrane protein. Membrane raft. Cytoplasm. Cytoplasmic vesicle, clathrin-coated vesicle.

Target Protein Families

ABC transporter superfamily, ABCB family, Multidrug resistance exporter (TC 3.A.1.201) subfamily

Target Synonyms

ABC 21; ABC B4; ABC21; ABCB 4; Abcb4; ABCB4 protein; ATP binding cassette sub family B MDR/TAP member 4; ATP binding cassette sub family B member 4; ATP-binding cassette sub-family B member 4; GBD1; ICP3; MDR 3; MDR2; MDR2/3; MDR3; MDR3 P glycoprotein; MDR3 P gp; MDR3_HUMAN; Multidrug resistance protein 3; Multiple drug resistance 3; P glycoprotein 3 ; P-glycoprotein 3; PFIC 3; PFIC3; PGY 3; PGY3

Target Background

The membrane-associated protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the MDR/TAP subfamily. Members of the MDR/TAP subfamily are involved in multidrug resistance as well as antigen presentation. This gene encodes a full transporter and member of the p-glycoprotein family of membrane proteins with phosphatidylcholine as its substrate. The function of this protein has not yet been determined; however, it may involve transport of phospholipids from liver hepatocytes into bile. Alternative splicing of this gene results in several products of undetermined function.