background:
ATP-binding cassette (ABC) transporters are an evolutionarily conserved family of widely-expressed proteins that use ATP hydrolysis to catalyze the transport of various molecules across extracellular and intracellular membranes. Eukaryotic ABC transporters are largely responsible for trafficking hydrophobic compounds either within the cell as part of a metabolic process, outside the cell for transport to other organs, or for secretion from the body. The cholesterol-responsive transporter, ABCA7, maps to human chromosome 19 and mouse chromosome 10 and has been reported as a candidate regulator of ceramide transport in epidermal lipid reorganization. High expression levels of ABCA7 have been reported in myelolymphatic tissues, reticuloendothelial cells, peripheral leukocytes, thymus, spleen and bone marrow. This expression pattern of the two alternatively-spliced isoforms also indicates an involvement in lipid homeostasis in cells of the immune system, though the complete role of ABCA7 is not yet known. Full-length type I ABCA7 has shown plasma membrane localization, while the type II splicing variant has shown expression predominantly in the endoplasmic reticulum.
Function:
Plays a role in phagocytosis by macrophages of apoptotic cells. Binds APOA1 and may function in apolipoprotein-mediated phospholipid efflux from cells. May also mediate cholesterol efflux. May regulate cellular ceramide homeostasis during keratinocytes differentiation.
Subcellular Location:
Cell membrane; Multi-pass membrane protein. Golgi apparatus membrane; Multi-pass membrane protein. Endosome membrane; Multi-pass membrane protein. Note=Localizes to cell membrane ruffles and phagocytic cups of macrophages stimulated with C1q or apoptotic cells. Localizes to the cytoplasm of resting macrophages, probably in Golgi and endosomes. Localizes to the apical brush border of cells in the proximal tubules of kidney. Isoform 2 may localize to the endoplasmic reticulum.
Tissue Specificity:
Expressed in leukocytes (at protein level). Widely expressed. Highly expressed in myelo-lymphatic tissues including peripheral leukocytes, thymus, spleen and bone marrow. Isoform 2 is more abundant in lymph node, spleen, thymus and trachea than isoform 1 which is more strongly expressed in brain and bone marrow.
Similarity:
Belongs to the ABC transporter superfamily. ABCA family.
Contains 2 ABC transporter domains.
Database links:
UniProtKB/Swiss-Prot: Q8IZY2.3
Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications.
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