Protein Domain : Sip3, PH domain IPR042067

Type	Domain
Description	This entry represents the pleckstrin homology (PH) domain found in Sip3 and its paralogue, Lam1 (also known as Ysp1), from budding yeasts. They have an N-terminal Bin/Amphiphysin/Rvs (BAR) domain followed by a PH domain, and a C-terminal StART-like domain. They may be involved in sterol transfer between intracellular membranes [ ]. This domain can also be found in uncharacterized protein C19A8.02 from fission yeasts. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner [ ]. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity []. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane []. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes [].
Short Name	Sip3_PH