ABCA4 - ATP binding cassette subfamily A member 4

Function

Flippase that catalyzes in an ATP-dependent manner the transport of retinal-phosphatidylethanolamine conjugates like the 11-cis and all-trans isomers of N-retinylidene-phosphatidylethanolamine from the lumen to the cytoplasmic leaflet of photoreceptor outer segment disk membranes, where N-cis-retinylidene-phosphatidylethanolamine (N-cis-R-PE) is then isomerized to its all-trans isomer (N-trans-R-PE) and reduced by RDH8 to produce all-trans-retinol (all-trans-rol) and therefore prevents the accumulation of excess of 11-cis-retinal and its schiff-base conjugate and the formation of toxic bisretinoid (PubMed:24097981, PubMed:22735453, PubMed:23144455, PubMed:20404325, PubMed:10075733, PubMed:29847635, PubMed:33375396). May display both ATPase and GTPase activity that is strongly influenced by the lipid environment and the presence of retinoid compounds (PubMed:22735453). Binds the unprotonated form of N-retinylidene-phosphatidylethanolamine with high affinity in the absence of ATP, and ATP binding and hydrolysis induce a protein conformational change that causes the dissociation of N-retinylidene-phosphatidylethanolamine (By similarity).

Gene Regulons