ABC transporter A (IPR026082)

Short name: ABCA

Overlapping homologous superfamilies


Family relationships


ATP-binding cassette transporters (ABC) are multipass transmembrane proteins that use the energy of ATP hydrolysis to transport substrates across membrane bilayers. Members of ABC transporter subfamily A are full-length transporters [PMID: 23103747], which consist of a single long polypeptide chain organised into two tandemly arranged halves. Each half contains a membrane-spanning domain (MSD) followed by a cytoplasmic nucleotide binding domain (NBD) [PMID: 11320094]. Several members of this group have been shown to mediate the transport of a variety of physiologic lipid compounds, such as sterols, phospholipids and bile acids [PMID: 16540294].

ABCA7 plays a role in clearance of apoptotic cells by affecting their phagocytosis [PMID: 16908670]. In the human visual cycle, ABCA4 acts as an inward-directed retinoid flipase, retinoid substrates imported by ABCA4 from the extracellular or intradiscal (rod) membrane surfaces to the cytoplasmic membrane surface are all-trans-retinaldehyde (ATR) and N-retinyl-phosphatidyl-ethanolamine (NR-PE). Once transported to the cytoplasmic surface, ATR is reduced to vitamin A by trans-retinol dehydrogenase (tRDH) and then transferred to the retinal pigment epithelium (RPE) where it is converted to 11-cis-retinal. ABCA4 may also play a role in photoresponse, removing ATR/NR-PE from the extracellular photoreceptor surfaces during bleach recovery [PMID: 10075733]. It has been suggested that ABCA9 plays a role in monocyte differentiation and lipid homeostasis [PMID: 12150964].

GO terms

Biological Process

GO:0055085 transmembrane transport

Molecular Function

GO:0042626 ATPase activity, coupled to transmembrane movement of substances

Cellular Component

GO:0016021 integral component of membrane

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.