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FLASH GENE
Symbol ABCB4 contributors: mct - updated : 28-06-2015
HGNC name ATP-binding cassette, sub-family B (MDR/TAP), member 4
HGNC id 45
PROTEIN
PHYSICAL PROPERTIES
STRUCTURE
motifs/domains
  • ABC transporter, traffic ATPase with two ATP binding
  • two transmembrane (2TM) domains (2x6 segments), localized to the hepatocyte canalicular membrane
    • conjugated GlycoP
    HOMOLOGY
    intraspecies homolog to ABCB1
    Homologene
    FAMILY
  • ATP binding cassette superfamily
  • subfamily B (MDR/TAP)
    • CATEGORY transport carrier
    SUBCELLULAR LOCALIZATION     plasma membrane
    basic FUNCTION
  • involved in phosphatidylcholine translocation into the bile
  • critical trans-locator for phospholipids across canalicular membranes of hepatocytes
  • liver-specific membrane transporter of phosphatidylcholine, a major and exclusive component of bile
  • translocates phosphatidylcholine from the inner to the outer leaflet of the canalicular membrane
  • ABCB4 and ATP8B1 cooperate to protect hepatocytes from bile salts
  • might play a critical role in glucose homeostasis
  • plays an important role in protecting the liver from bile acids
  • may be involved in the transport of a broad array of drugs, because ABCB4 shows high amino acid homology to ABCB1 that plays an important role in transporting of various clinical drugs such as digoxin and paclitaxel
  • located in nonrafts, but not in rafts, is predominantly involved in the efflux of phospholipids and other substrates
    • CELLULAR PROCESS
    PHYSIOLOGICAL PROCESS
    PATHWAY
    metabolism
    signaling
    a component
    INTERACTION
    DNA
    RNA
    small molecule
    protein
  • NFYA, NFYB, NFYC can act as a transcriptional activator of ABCB4
  • interaction of ABCB4 with SLC9A3R1 through its PDZ-like motif plays a critical role in the regulation of ABCB4 expression and stability at the canalicular plasma membrane
    • cell & other
    REGULATION
    Other ABCB4 activity is regulated by phosphorylation, in particular, of N-terminal residues
    ASSOCIATED DISORDERS
    corresponding disease(s) PFIC3 , LPAC
    Other morbid association(s)
    TypeGene ModificationChromosome rearrangementProtein expressionProtein Function
    constitutional germinal mutation      
    cause intrahepatic cholestasis of pregnancy, with normal gamma-GT and may be associated with stillbirths and gallstone disease
    constitutional germinal mutation      
    splicing mutations cause intrahepatic cholestasis of pregnancy in women with high gamma-glutamyl transpeptidase (Tavian 2009)
    Susceptibility
  • to drug-induced cholestasis
  • to higher BMI and triglyceride and cholesterol levels
  • to to drug-induced cholestatic liver injury
    • Variant & Polymorphism SNP , other
  • polylmorphisms increasing drug-induced cholestasis (Lang 2007)
  • SNP C.504C > T associated with higher BMI and triglyceride and cholesterol levels (Acalovschi 2009)
  • g.-1584C>T and g.-1014A>G, may be associated with a susceptibility. to drug-induced cholestatic liver injury
    • Candidate gene
    Marker
    Therapy target
    ANIMAL & CELL MODELS