ABCB4

Gene Information

Official Symbol: ABCB4
Official Name: ATP binding cassette subfamily B member 4
Aliases and Previous Symbols: N/A
Entrez ID: 5244
UniProt: P21439
Interactions: BioGRID
PubMed articles: Open PubMed
OMIM: Open OMIM

Function Summary

Entrez Summary: 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. [provided by RefSeq, Jul 2008].
UniProt Summary: 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 (By similarity). {ECO:0000250|UniProtKB:P21440, ECO:0000269|PubMed:17523162, ECO:0000269|PubMed:21820390, ECO:0000269|PubMed:23468132, ECO:0000269|PubMed:24045840, ECO:0000269|PubMed:24594635, ECO:0000269|PubMed:24723470, ECO:0000269|PubMed:24806754, ECO:0000269|PubMed:28012258, ECO:0000269|PubMed:7957936, ECO:0000269|PubMed:8898203, ECO:0000269|PubMed:9366571}.

Pfam Domains GO Terms

CRISPR Data

Compound Hit Most Correlated Genes in Chemogenomics Tissues where Essential in the Avana Dataset (DepMap 20Q1)

Screen	Score
Actinomycin-D 0.001μM R00 exp3	-2.65
DABN 20μM R00 exp17	-1.98
PU-H71 1μM R08 exp515	-1.78

Global Fraction of Cell Lines Where Essential: 0/739

Tissue	Fraction Of Cell Lines Where Essential
1290807.0	0/1
909776.0	0/1
bile duct	0/28
blood	0/28
bone	0/26
breast	0/33
central nervous system	0/56
cervix	0/4
colorectal	0/17
esophagus	0/13
fibroblast	0/1
gastric	0/16
kidney	0/21
liver	0/20
lung	0/75
lymphocyte	0/16
ovary	0/26
pancreas	0/24
peripheral nervous system	0/16
plasma cell	0/15
prostate	0/1
skin	0/24
soft tissue	0/9
thyroid	0/2
upper aerodigestive	0/22
urinary tract	0/29
uterus	0/5

Essentiality in NALM6

Essentiality Rank: 17538
Expression level (log2 read counts): 5.31

Expression Distribution