[Progress in the research on the ABCA gene family of vertebrates]

The ATP-binding cassette (ABC) superfamily of genes encodes membrane proteins that transport many kinds of substrates across membranes. Based on amino acid sequence similarities and phylogeny, 48 ABC genes in the human genome were divided into seven subfamilies: ABCA to ABCG. Among them, ABCA transporters have a unique topology and the members of this subfamily had expanded twice by gene duplication after the divergences between amphibian and mammal, respectively. The new duplicated genes are well retained in rodent and carnivore, while half of them became pseudogenes or were absent in primate genome. Transporters of the ABCA subclass were responsible for critical physiological functions in the transmembrane transport of endogenous lipid and cholesterol substrates. Mutations of members of ABCA are associated with human genetic diseases.