proteins are involved in the process
At present, the most important role of phosphoinositides in humans is that they regulate cell signaling pathways via recruitment of proteins with pleckstrin homology (PH) domains to the plasma membrane. There is growing evidence that some PH domain-containing proteins are involved in the process of neurodegeneration and other human diseases. Although the roles of PH domain-containing proteins are complex and poorly understood, it is generally believed that they are recruited to membranes in response to specific signals. For example, PIP kinases (PIPKs) are activated in response to various signals, such as increases PHB2 gene in intracellular Ca++, activation of tyrosine kinases, and the addition of extracellular stimuli. PIPKs are activated by binding of the calcium-calmodulin complex to the PH domain and produce the second messengers DAG and PI(OH)P. Once these lipids are produced, they stimulate the activity of effector proteins by recruiting them to specific membrane compartments.
The phosphoinositide signaling pathway has recently gained much interest due to the discovery that several protein kinases (PIKKs), including ATM, ATR, and DNA-PKcs, contain a bimodal regulatory region called a forkhead-associated (FHA) domain.