Pleckstrin is the major substrate of protein kinase C in platelets, although its precise function is not known. This protein contains two pleckstrin homology (PH) domains. This particular domain has the same name as the protein because it was first detected in pleckstrin. The PH domain is usually made up of 100 amino acid residues, and is found in many proteins that are involved in intracellular signaling. The true domain function is also not known, but it has been shown to bind to the following: the beta/gamma subunit of heterotrimeric G proteins, phosphatidylinositol-4,5-bisphosphate (or PIP2, e.g. lipids), phosphorylated Serine/Threonine residues, and membranes.
The N terminal PH domain of pleckstrin is 113 amino acid residues long. Its structure consists of an up-and-down beta-barrel made of 7 antiparallel beta-strands and a C terminal amphiphilic alpha-helix which caps one end of the barrel.