Pleckstrin homology domain as an inositol compound binding module

Many of the proteins that participate in cell signalling contain structural modules involved in regulatory interactions between components of signal transduction cascades. One of such modules is the pleckstrin homology (PH) domain, a region of approximately 120 amino acids that can form an electrostatically polarized tertiary structure. Several molecules such as inositol 1,4,5-trisphosphate/phosphatidylinositol 4,5-bisphosphate, the βγ-subunits of heterotrimeric G proteins and protein kinase C have been proposed as common ligands for the PH domain. Through these potential interactions, the PH domain has been proposed to play a role in membrane recruitment of proteins containing the PH domain, thus targeting them to appropriate cellular compartment or enabling them to interact with other components of the signal transduction pathway. In this review, we mainly focus on membrane targeting through the binding to inositol phosphates/phosphoinositides.