Tbio ABCB4 Phosphatidylcholine translocator ABCB4

Protein Summary

Description

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). 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 Accession IDs

• P21439
• A0A2V7
• A4D1D3
• A4D1D4
• A4D1D5
• D6W5P3
• D6W5P4
• Q14813

Gene Name

• ABCB4

Ensembl ID

• ENST00000265723
• ENSP00000265723
• ENSG00000005471
• ENST00000358400
• ENSP00000351172
• ENST00000359206
• ENSP00000352135
• ENST00000453593
• ENSP00000392983
• ENST00000649586
• ENSP00000496956

Symbol

• MDR3
• PGY3
• GBD1
• ICP3
• MDR2
• MDR3
• PGY3
• ABC21
• MDR2/3
• PFIC-3

Knowledge Table

Most Knowledge About	Knowledge Value (0 to 1 scale)
molecular function	0.99
protein domain	0.85
gene perturbation	0.8
metabolite	0.78
kinase perturbation	0.76

Protein Classes

PANTHER Classes

Protein / ... / Serine Protease / Phosphatidylcholine Translocator Abcb4

Protein / ... / Cysteine Protease / Phosphatidylcholine Translocator Abcb4

DTO Classes

Protein / Transporter / Atp-binding Cassette Transporter Family / Abcb Subfamily / Phosphatidylcholine Translocator Abcb4

IDG Development Level Summary

Tdark

These are targets about which virtually nothing is known. They do not have known drug or small molecule activities
- AND - satisfy two or more of the following criteria:

Pubmed score: 1616.11   (req: < 5)

Gene RIFs: 136   (req: <= 3)

Antibodies: 203   (req: <= 50)

Tbio

These targets do not have known drug or small molecule activities
- AND - satisfy two or more of the following criteria:

Pubmed score: 1616.11   (req: >= 5)

Gene RIFs: 136   (req: > 3)

Antibodies: 203   (req: > 50)

- OR - satisfy the following criterion:

Gene Ontology Terms: 18

Tchem

Target has at least one ChEMBL compound with an activity cutoff of < 30 nM - AND - satisfies the preceding conditions

Active Ligand: 0

Tclin

Target has at least one approved drug - AND - satisfies the preceding conditions

Active Drug: 0