?
Neuronal growth-associated proteins Pleckstrin homology (PH) domain nGAP (also called RASAL2/RAS protein activator like-3) is a member of the RasSynGAP family along with DOC-2/DAB2-interacting protein (DAB2IP) and synaptic RasGAP (SynGAP). nGAPs are growth cone markers found in multiple types of neurons. There are many nGAPs including Cap1 (Adenylate cyclase-associated protein 1), Capzb (Capping protein (actin filament) muscle Z-line, beta), Clptm1 (Cleft lip and palate associated transmembrane protein 1), Cotl1 (Coactosin-like 1), Crmp1 (Collapsin response mediator protein 1), Cyfip1 (Cytoplasmic FMR1 interacting protein 1), Fabp7 (Fatty acid binding protein 7, brain), Farp2 (FERM, RhoGEF and pleckstrin domain protein 2), Gap43 (Growth associated protein 43), Gnao1 (Guanine nucleotide binding protein (G protein), alpha activating activity polypeptide O), Gnai2 (Guanine nucleotide binding protein (G protein), alpha inhibiting 2), Pacs1 (Phosphofurin acidic cluster sorting protein 1), Rtn1 (Reticulon 1), Sept2 (Septin 2), Snap25 (Synaptosomal-associated protein 25), Strap (Serine/threonine kinase receptor associated protein), Stx7 (Syntaxin 7), and Tmod2 (Tropomodulin 2). PH domains are only found in eukaryotes. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. 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.
|