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Symbol ABCB1 contributors: mct - updated : 07-09-2020
HGNC name ATP-binding cassette, sub-family B (MDR/TAP), member 1
HGNC id 40
  • two ATP binding and two transmembrane (2TM) domains (2 x 6 segments)
  • two hydrophobic and hydrophilic domains linked by a highly charged region of approximately 90 AAs, the "linker domain" mediating protein interactions
  • lipid translocase of broad specificity
  • conjugated GlycoP
    interspecies homolog to rattus Abcb1a (87.6 pc)
    homolog to murine Abcb1a (87.5 pc)
  • ABC (ATP binding cassette) transporter superfamily
  • multidrug resistance exporter (TC 3.A.1.201) subfamily
  • subfamily B (MDR/TAP)
  • CATEGORY enzyme , transport carrier
    SUBCELLULAR LOCALIZATION     plasma membrane
    basic FUNCTION
  • ABC transporter, traffic ATPase, emergy-dependent efflux pump responsible for decreased drug accumulation in multidrug resistant cells
  • potentially implicated in cholesterol transport
  • may maintain neural stem/progenitor cells in an undifferentiated state and could be a neural stem/progenitor marker
  • cause multidrug resistance in tumor cell lines selected with lipophilic anticancer drugs
  • drug efflux transporter expressed in various tissues and playing an important role in the absorption and elimination of many drugs and xenobiotics
  • is involved in BTB (blood–testis barrier) restructuring during spermatogenesis but ABCB1–mediated restructuring does not “open up” the BTB to make it freely permeable to drugs
  • innate immune inflammatory response in the trabecular meshwork (TM) may play a role in the ABCB1 detoxification of potentially harmful constituents in the aqueous humor (pMID: 25802484)
  • important and selective elements of the blood-brain barrier (BBB), that actively contribute to brain homeostasis
  • ABCB1 is involved in neo-absorbed vitamin D efflux by the enterocytes and it also contributes to vitamin D transintestinal excretion and likely impacts vitamin D status
    text cholesterol transport
    a component
  • ABCB1 and an integrated component of the occludin/zonula occludens 1 (TJP1) adhesion complex at the BTB, structurally interacted with PTK2, creating the OCLN/TJP1/PTK2/ABCB1 regulatory complex
    small molecule nucleotide,
  • ATP
  • protein
  • APEX1 stably interacts with Y-box-binding protein 1 (YBX1), and acts as its coactivator for the expression of multidrug resistance gene ABCB1, thereby causing drug resistance
  • involved in regulating BTB dynamics, likely via its interaction with PTK2, which modulates the phosphorylation status of the OCLN/TJP1 protein complex
  • PPP2R3C negatively regulates ABCB1 expression and function
  • ABCB1 functional activity is affected by TLR4 agonists suggesting that modulation of TLR4 is important in ABCB1 function
  • crucial role of ABCB1 in the APP transport and oxidative stress may interfere with this process
  • cell & other
    activated by function can be stimulated in the presence of cholesterol
    induced by THRA, THRB (induces ABCB1 gene expression in a thyroid hormone (TH)-dependent manner)
    Other upregulated by P/CAF : NFY heterodimer
    corresponding disease(s)
    Other morbid association(s)
    TypeGene ModificationChromosome rearrangementProtein expressionProtein Function
    tumoral   amplification    
    amplified in sarcoma cell lines
    tumoral     --over  
    in acute myeloid leukemia and cancer cell lines
    tumoral     --low  
    low ABCB1/low BAALC expression identifies a subgroup of intermediate cytogenetic risk AML patients with a remarkably good long-term outcome achieved by chemotherapy alone
    tumoral     --low  
    in breast tumors was associated with triple-negative subtype
    tumoral     --low  
    may promote colorectal carcinogenesis through increasing intracellular exposure to carcinogenic ABCB1 substrates
  • to inflammatory bowel disease(IBD)
  • to renal epithelial tumors
  • Variant & Polymorphism other Ala893 increases the risk of IBD
    C3435T increases the risk of renal tumors
    Candidate gene
    Marker EPS8, as ABCB1 and WT1, may be a clinically valuable biomarker for assessing the outcome of acute lymphoblastic leukemia (ALL) patients
    Therapy target