Protein Domain : ASAP, PH domain IPR037844

Type	Domain
Description	This entry represents the PH domain of Arf-GAP with SH3 domain, ANK repeat and PH domain-containing proteins (ASAPs). ASAPs (ASAP1, ASAP2, and ASAP3) function as Arf-specific GTPase-activating proteins (GAPs), participate in rhodopsin trafficking, are associated with tumour cell metastasis, modulate phagocytosis, promote cell proliferation, facilitate vesicle budding, Golgi exocytosis, and regulate vesicle coat assembly via a Bin/Amphiphysin/Rvs domain [ , , ]. Each member has a BAR, PH, Arf GAP, Ank repeat and proline rich domains. ASAP1 and ASAP2 also have a SH3 domain at the C terminus []. The ASAP family is named for the first identified member, ASAP1 [].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	PH_ASAP