Investigating lipid signalling: it's all about finding the right PI.
Phosphoinositides are well-known components of cellular signal transduction pathways and, more recently, have been shown to play important roles in organelle identity and targeting determinants for various cytosolic proteins. Conversion of PtdIns into its various phosphorylated derivatives, such as PtdIns4P and PtdIns(4,5)P(2), is accomplished by a series of distinct lipid kinase and lipid phosphatase activities that are localized to specific subcellular membranes. As a result, production of distinct PtdIns forms is thought to be largely dependent on the access of these enzymes to their PtdIns or PtdInsP substrates. Interestingly, an investigation of two different PIS (PtdIns synthase) isoforms by Lofke et al. in this issue of the Biochemical Journal now indicates that the ability of PtdIns to be converted into downstream PtdInsPs may depend upon the PIS isoform from which it was synthesized.
Nielsen
Erik
E
Deparment of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA. nielsene@umich.edu
D000818:Animals; D017360:Arabidopsis / Q000166:cytology / Q000378:metabolism; D051607:CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase / Q000378:metabolism; D050356:Lipid Metabolism; D010716:Phosphatidylinositols / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism; D015398:Signal Transduction
D010716:Phosphatidylinositols; D051607:CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase