P-glycoprotein 3 (PGY3, multidrug resistance protein 3, MDR3, ATP-binding cassette subfamily B member 4, ABC4)

Introduction

Mediates the translocation of phosphatidylcholine across the canalicular membrane of hepatocytes.

Function

• energy-dependent efflux pump responsible for decreased drug accumulation in multidrug-resistant cells
• mediates translocation of phosphatidylcholine across the canalicular membrane of the hepatocyte
• human MDR3 is not capable of conferring drug resistance

Structure

• belongs to the ABC transporter family, multidrug resistance exporter (TC 3.A.1.201) subfamily
• contains 2 ABC transmembrane type-1 domains
• contains 2 ABC transporter domains

Compartment

membrane

Alternative splicing

named isoforms=2

Pathology

• defects in ABCB4 are the cause of
  • familial intrahepatic cholestasis 3
  • intrahepatic cholestasis of pregnancy
  • cholelithiasis
• genetic variations in ABCB4 may play a role in drug- induced cholestasis causing liver damage

More general terms

• P-glycoprotein (gp170) or multidrug-resistance glycoprotein
• ATP-binding cassette sub-family B (ABC transporter-B, ABCB)
• phosphoprotein

Additional terms

• familial intrahepatic cholestasis 3

Database

• UniProt: http://www.uniprot.org/uniprot/P21439.html
• OMIM: https://mirror.omim.org/entry/147480
• OMIM: https://mirror.omim.org/entry/171060
• OMIM: https://mirror.omim.org/entry/600803
• OMIM: https://mirror.omim.org/entry/602347
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=5244