Differential expression of putative transbilayer amphipath transporters

Abstract

The aminophospholipid translocase transports phosphatidylserine and phosphatidylethanolamine from one side of a bilayer to another. Cloning of the gene encoding the enzyme identified a new subfamily of P-type ATPases, proposed to be amphipath transporters. As reported here, mammals express as many as 17 different genes from this subfamily. Phylogenetic analysis reveals the genes to be grouped into several distinct classes and subclasses. To gain information on the functions represented by these groups, Northern analysis and in situ hybridization were used to examine the pattern of expression of a panel of subfamily members in the mouse. The genes are differentially expressed in the respiratory, digestive, and urogenital systems, endocrine organs, the eye, teeth, and thymus. With one exception, all of the genes are highly expressed in the central nervous system (CNS); however, the pattern of expression within the CNS differs substantially from gene to gene. These results suggest that the genes are expressed in a tissue-specific manner, are not simply redundant, and may represent isoforms that transport a variety of different amphipaths.

Localization, Purification, and Functional Reconstitution of the P4-ATPase Atp8a2, a Phosphatidylserine Flippase in Photoreceptor Disc Membranes

“…1A). Detection in the testis by RT-PCR is in general agreement with earlier studies showing high atp8a2 expression in the testis by Northern blot analysis (28).…”

“…The P 4 -ATPase Atp8a2 was identified as a membrane protein present in photoreceptor outer segment preparations. atp8a2 has been previously reported to be expressed in the testis as a 4.5-kb mRNA with high levels occurring during early spermatid development (28). The biochemical properties of this member of the P 4 -ATPase family, however, have not been investigated to date.…”

Deletions of IKZF1 and SPRED1 are associated with poor prognosis in a population-based series of pediatric B-cell precursor acute lymphoblastic leukemia diagnosed between 1992 and 2011

“…17,19,27,32,33 However, three of the presently identified gene targets, ADD3, ATP10A and PAN3, have been less emphasized in previous studies. ADD3 plays an important role in the skeletal organization of the cell membrane in erythrocytes, 34 ATP10A is an aminophospholipid translocase responsible for transporting amphipathic molecules, 35 and PAN3 is involved in degradation of poly(A) tails in cytoplasmic mRNA. 36 Both ADD3 and PAN3 have been reported to play a role in ALL -ADD3 is a NUP98 partner in T-ALL 37 and significantly associated with a gene expression cluster group with poor outcome in high risk BCP ALL 38 and PAN3 is recurrently deleted in high hyperdiploidy ALL.…”

Atp8b1 deficiency in mice reduces resistance of the canalicular membrane to hydrophobic bile salts and impairs bile salt transport

“…ATP8B1 is a member of the type 4 subfamily of P-type ATPases. [6][7][8] Proteins of this family translocate phospholipids from the outer to the inner leaflet of biological membranes and are termed flippases. [9][10][11][12] In the liver, ATP8B1 localizes to the apical membrane of epithe-lial cells, including hepatocytes and bile duct epithelial cells (cholangiocytes).…”