The uses and limitations of the analysis of cellular phosphoinositides by lipidomic and imaging methodologies

• MS methods to analyse and quantify some phosphoinositides have been developed.
• Imaging methods identify location of all signaling phosphoinositides.
• Complementary use of all approaches characterizes signaling.
• The importance of acyl chain composition of phosphoinositides is becoming apparent.

The advent of mass spectrometric methods has facilitated the determination of multiple molecular species of cellular lipid classes including the polyphosphoinositides, though to date methods to analyse and quantify each of the individual three PtdInsP and three PtdInsP2 species are lacking. The use of imaging methods has allowed intracellular localization of the phosphoinositide classes but this methodology does not determine the acyl structures. The range of molecular species suggests a greater complexity in polyphosphoinositide signaling than yet defined but elucidating this will require further method development to be achieved. This article is part of a Special Issue entitled Tools to study lipid functions.