The phosphatidylinositol phosphates represent a small percentage of total membrane phospholipids. However, they play a critical role in the generation and transmission of cellular signals. PtdIns-(3,4,5)-P3 can serve as an anchor for the binding of signal transduction proteins bearing pleckstrin homology (PH) domains. Centuarin α and the Akt-family of GTPase activating proteins are examples of PtdIns-(3,4,5)-P3-binding proteins. Protein-binding to PtdIns-(3,4,5)-P3 is important for cytoskeletal rearrangements and membrane trafficking. PtdIns-(3,4,5)-P3 is resistant to cleavage by PI-specific phospholipase C (PLC). Thus, it is likely to function in signal transduction as a modulator in its own right, rather than as a source of inositol tetraphosphates. For further reading on inositol phospholipids, see also references and .
