Separation and detection of all phosphoinositide isomers by ESI-MS

Phosphoinositides (Pls) play fundamental roles as signalling molecules in numerous cellular processes Direct analysis of Pls is typically accomplished by metabolic labelling with H-3-inositol or inorganic P-32 followed by deacylation, ion-exchange chromatography and flow scintillation detection This analysis is laborious, time-consuming, and involves massive amounts of radioactivity To overcome these limitations we established a robust, non-radioactive LC-ESI-MS assay for the separation and analysis of deacylated Pis that allows discrimination of all isomers without the need for radioactive labelling We applied the method to various cell types to study the PI levels upon specific stimulation (c) 2010 Elsevier B V All rights reserved