Transports lipids such as glucosylceramides from the outer to the inner leaflet of lamellar granules (LGs) membrane, whereby the lipids are finally transported to the keratinocyte periphery via the trans-Golgi network and LGs and released to the apical surface of the granular keratinocytes to form lipid lamellae in the stratum corneum of the epidermis, which is essential for skin barrier function (PubMed:16007253, PubMed:20869849). In the meantime, participates in the transport of the lamellar granules-associated proteolytic enzymes, in turn regulates desquamation and keratinocyte differentiation (PubMed:19179616). Furthermore, is essential for the regulation of cellular cholesterol homeostasis by regulating ABCA1-dependent cholesterol efflux from macrophages through interaction with NR1H2 and ABCA1 (By similarity). Plays pleiotropic roles in regulating glucose stimulated insulin secretion from beta cells, regulating the morphology and fusion of insulin granules, lipid raft abundance and the actin cytoskeleton (By similarity). Also involved in lung surfactant biogenesis (By similarity). ATP + H2O + phospholipidSide 1 = ADP + phosphate + phospholipidSide 2. ATP + beta-D-glucosylceramide(in) + H2O = ADP + beta-D-glucosylceramide(out) + H(+) + phosphate Interacts with NR1H2 and ABCA1; this interaction is required for ABCA1 localization to the cell surface and is necessary for its normal activity and stability. Localizes in the limiting membrane of the lamellar granules (LGs) (PubMed:17927575). Trafficks from the Golgi apparatus to the lamellar granules (LGs) at the cell periphery in the uppermost granular layer keratinocytes where ABCA12-positive LGs fuse with the keratinocyte-cell membrane to secrete their lipid content to the extracellular space of the stratum corneum (PubMed:16007253, PubMed:17927575). Co-localizes through the Golgi apparatus to the cell periphery with glucosylceramide (PubMed:17927575). Additional isoforms seem to exist. Mainly expressed in the stomach, placenta, testis and fetal brain (PubMed:12697999). Expressed in the upper epidermal layers, mainly the granular layers, of skin (PubMed:16007253, PubMed:17591952, PubMed:17927575). Expressed throughout the normal interfollicular epidermis with prominent expression in the stratum granulosum (PubMed:19179616). Expressed in alpha and beta cells of pancreatic islets (PubMed:32072744). At about 6 to 9 weeks estimated gestational age (EGA), expressed in the periderm during the early period when the two-layered epidermis form. At 10 to 13 weeks EGA, expressed in the entire epidermis with high expression in periderm until to 14 to 22 weeks EGA. Up-regulated during keratinization (PubMed:16007253). Up-regulated after 15 weeks estimated gestational age (EGA) (PubMed:17591952). Highly up-regulated by PPARG activators such as ciglitazone, troglitazone, and the PPARD activator GW 0742 in time- and dose-dependent manner but independently of keratinocyte differentiation. In addition, modestly up-regulated by the NR1H3 and NR1H2 activator TO901317 in an keratinocyte differentiation-independent manner (PubMed:17611579). Up-regulated by N-(hexanoyl)sphing-4-enine in a time- and dose-dependent manner or by glucosyltransferase inhibitors, ceramidase inhibitors and sphingomyelin synthase inhibitors that increase endogenous ceramide levels and induce ABCA12 expression via the PPARD signaling pathway (PubMed:19429679). Up-regulated by N-acetylsphingosine in a time- and dose-dependent manner via the PPARD signaling pathway (Probable). Multifunctional polypeptide with two homologous halves, each containing a hydrophobic membrane-anchoring domain and an ATP binding cassette (ABC) domain. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Belongs to the ABC transporter superfamily. ABCA family. Database for mutations in ABC proteins