Nature Biotechnology
21, 813 - 817 (2003)
Published online: 15 June 2003; | doi:10.1038/nbt837
Phosphoinositide profiling in complex lipid mixtures using
electrospray ionization mass spectrometryMarkus R Wenk1, Louise Lucast1, Gilbert Di Paolo1, Anthony J Romanelli2, Sharon F Suchy4, Robert L Nussbaum4, Gary W Cline2, Gerald I Shulman2, Walter McMurray3
& Pietro De Camilli11
Howard Hughes Medical Institute, Department of
Cell Biology, Yale University School of Medicine, Boyer Center for Molecular
Medicine, 295 Congress Avenue, New Haven,
Connecticut 06511, USA. 2
Howard Hughes Medical Institute, Department of
Internal Medicine, Yale University School of Medicine, Congress Avenue
Building, 300 Cedar Street, New Haven,
Connecticut 06511. 3
The W.M. Keck Mass Spectrometry Resource, Yale
University School of Medicine, Boyer Center for Molecular Medicine,
295 Congress Avenue, New Haven,
Connecticut 06511, USA. 4
National Human Genome Research Institute, National
Institutes of Health, 49 Convent Dr., Bethesda,
Maryland 20892-4472, USA.
Correspondence should be addressed to Markus R Wenk markus.wenk@yale.eduPhosphoinositides (phosphorylated derivatives of
phosphatidylinositol, PI) are versatile intracellular signaling lipids whose
occurrence in low concentrations complicates direct mass measurements1,
2,
3. Here we present a sensitive method to detect, identify and
quantify phosphatidylinositol phosphate (PIP) and phosphatidylinositol
bisphosphate (PIP2) with different fatty acid compositions
(phosphoinositide profiles) in total lipid extracts by electrospray ionization
mass spectrometry (ESI-MS). Using this method, we detected elevated
concentrations of PIP2 in human fibroblasts from patients with Lowe
syndrome, a genetic disorder that affects phosphoinositide metabolism4. Saccharomyces cerevisiae cells deficient in enzymes involved
in PIP metabolism—Sac1p, a phosphoinositide phosphatase5,
and Vps34p and Pik1p, a PI 3-kinase6 and PI 4-kinase7, respectively—showed not only different PIP concentrations but
also differential changes in PIP profiles indicating metabolic and/or
subcellular pooling. Mass spectrometric analysis of phosphoinositides offers
unique advantages over existing approaches and may represent a powerful
diagnostic tool for human diseases that involve defective phosphoinositide
metabolism.
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