Cloning, tissue distribution and sub-cellular localisation of phospholipase C X-domain containing protein (PLCXD) isoforms.
Phosphatidylinositol-specific phospholipase C (PI-PLC) enzymes comprise a small family of receptor-regulated phosphodiesterases that control many cellular processes by the regulation of cytosolic calcium and/or the activity of several protein kinases. To date, six distinct classes of PI-PLC are known to exist in mammals. Here we characterise a seventh class of PI-PLC, which contains only the catalytic X domain in its structure, termed phospholipase C X-domain containing protein (PLCXD). At least three tissue-specific PLCXD isoforms exist in humans, comprising hPLCXD-1, hPLCXD-2 and hPLCXD-3, with hPLCXD-2 exhibiting three C-terminal spliceforms (2.1, 2.2 and 2.3). Specific amino acids known to be essential for the catalytic function of PI-PLCs were found to be conserved in all three human PLCXDs and over-expression of hPLCXD-1, 2.1 and 3 in the HeLa cell line increased endogenous PI-PLC activity. Human PLCXD isoforms exhibited tissue-specific expression profiles in mice and humans and immunocytochemistry revealed distinct sub-cellular localisations when over-expressed in human cultured cell lines. These novel proteins may therefore possess fundamental, and as yet uncharacterised roles in cell physiology.
School of Medicine, University of St Andrews, Medical and Biological Sciences Building, North Haugh, St Andrews, Fife, KY16 9TF, UK.
Steven A
SA
Gellatly
Svetlana
S
Kalujnaia
Gordon
G
Cramb
D000818:Animals; D020134:Catalytic Domain; D003001:Cloning, Molecular; D006367:HeLa Cells; D006801:Humans; D042541:Intracellular Space / Q000201:enzymology; D007527:Isoenzymes / Q000145:classification / Q000235:genetics / Q000378:metabolism; D051379:Mice; D054801:Phosphoinositide Phospholipase C / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D014018:Tissue Distribution
D007527:Isoenzymes; D054801:Phosphoinositide Phospholipase C