| Primary Identifier | IPR039597 | Type | Domain |
| Short Name | M-RIP_PH |
| description | Myosin phosphatase-RhoA interacting protein (M-RIP) is proposed to play a role in myosin phosphatase regulation by RhoA. M-RIP contains two PH domains followed by a Rho binding domain (Rho-BD), and a C-terminal myosin binding subunit (MBS) binding domain (MBS-BD). The amino terminus of M-RIP with its adjacent PH domains and polyproline motifs mediates binding to both actin and Galpha. M-RIP brings RhoA and MBS into close proximity where M-RIP can target RhoA to the myosin phosphatase complex to regulate the myosin phosphorylation state. M-RIP does this via its C-terminal coiled-coil domain which interacts with the MBS leucine zipper domain of myosin phosphatase, while its Rho-BD, directly binds RhoA in a nucleotide-independent manner [, ].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 []. |
