Cloning, tissue distribution and sub-cellular localisation of phospholipase C X-domain containing protein (PLCXD) isoforms

• Published in: Biochemical and biophysical research communications 2012-08, Vol.424 (4), p.651-656
• Main Authors: Gellatly, Steven A., Kalujnaia, Svetlana, Cramb, Gordon
• Format: Article
• Language: English
• Subjects: Animals; Catalytic Domain; Cloning, Molecular; HeLa Cells; Humans; Immunocytochemistry; Intracellular Space - enzymology; Isoenzymes - classification; Isoenzymes - genetics; Isoenzymes - metabolism; Mice; Phosphoinositide; Phosphoinositide Phospholipase C - classification; Phosphoinositide Phospholipase C - genetics; Phosphoinositide Phospholipase C - metabolism; Phospholipase C; Phylogeny; PLCXD; Tissue Distribution; X-domain
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2012.06.079

► A phylogenetic analysis of PLC X-domain-containing proteins (PLCXDs) is presented. ► The tissue distribution of mouse and human PLCXD isoforms was determined. ► Lenti-viral expression of PLCXDs indicate isoform-specific subcellular locations. ► Over-expression of PLCXDs in HeLa cells results in enhanced PLC enzyme activity. 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.