ATPaseII,avanadate-sensitiveandphosphatidylserinedependent Mg 2؉ -ATPase, is a member of a subfamily of P-type ATPase and is presumably responsible for aminophospholipid translocation activity in eukaryotic cells. The aminophospholipid translocation activity plays an important physiological role in the maintenance of membrane phospholipid asymmetry that is observed in the plasma membrane as well as the membranes of certain cellular organelles. While the preparations of ATPase II from different sources share common fundamental properties, such as substrate specificity, inhibitor spectrum, and phospholipid dependence, they are divergent in several characteristics. These include specific ATPase activity and phospholipid selectivity. We report here the identification of four isoforms of ATPase II in bovine brain. These isoforms are formed by a combination of two major variations in their primary sequences and show that the structural variation of these isoforms has functional significance in both ATPase activity and phosholipid selectivity. Furthermore, studies with the phosphoenzyme intermediate of ATPase II and its recombinant isoforms revealed that phosphatidylserine is essential for the dephosphorylation of the intermediate. Without phosphatidylserine, ATPase II would be accumulated as phosphoenzyme in the presence of ATP, resulting in the interruption of its catalytic cycle.
Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia. Submicroscopic insertion of RARα into PML, resulting in PML-RARα from derivative chromosome 15, has been rarely reported. Herein, we describe a functional PML-RARα transcript from the long arm of derivative chromosome 17 in a patient with microgranular APL. The conventional karyotype showed normal chromosomes 15 and 17. It is interesting that interphase and metaphase fluorescence in situ hybridizations demonstrated a fusion signal on the long arm of one chromosome 17 homolog, with both PML and RARα still present on chromosomes 15 and 17, respectively, although the signal on one chromosome 15 was weaker, indicating partial loss of the PML gene. Reverse transcriptase–polymerase chain reaction revealed a transcript corresponding to a break cluster region 3 (bcr3) short form PML-RARα. To the best of our knowledge, this is the first report of an APL with a bcr3/short form PML-RARα transcript generated from derivative chromosome 17 due to submicroscopic insertion of the PML gene into the RARα locus.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.