The ATP-binding cassette 4
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
encodes the Multidrug resistance protein 3.
ABCB4 is associated with
progressive familial intrahepatic cholestasis type 3 and
intrahepatic cholestasis of pregnancy.
The membrane-associated
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
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 (
flippase
Flippases (rarely spelled flipases) are transmembrane lipid transporter proteins located in the membrane which belong to ABC transporter or P4-type ATPase families. They are responsible for aiding the movement of phospholipid molecules between th ...
activity). 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.
Cancer
ABCB4 gene has been observed progressively downregulated in
Human papillomavirus
Human papillomavirus infection (HPV infection) is caused by a DNA virus from the ''Papillomaviridae'' family. Many HPV infections cause no symptoms and 90% resolve spontaneously within two years. In some cases, an HPV infection persists and res ...
-positive
neoplastic keratinocytes derived from uterine cervical
preneoplastic lesions at different levels of malignancy.
For this reason, ABCB4 is likely to be associated with tumorigenesis and may be a potential prognostic marker for uterine cervical
preneoplastic lesions progression.
Other conditions that have been associated with mutations in this gene include
low phospholipid associated cholelithiasis syndrome, high gamma glutamyl transferase intrahepatic cholestasis of pregnancy, chronic cholangiopathy and adult biliary fibrosis.
[Sticova E, Jirsa M (2019) ABCB4 disease: Many faces of one gene deficiency. Ann Hepatol ]
References
Further reading
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External links
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