2k4p
From Proteopedia
Solution Structure of Ship2-Sam
Structural highlights
DiseaseSHIP2_HUMAN Defects in INPPL1 may be a cause of susceptibility to type 2 diabetes mellitus non-insulin dependent (NIDDM) [MIM:125853.[1] [2] Note=Genetic variations in INPPL1 may be a cause of susceptibility to metabolic syndrome. Metabolic syndrome is characterized by diabetes, insulin resistance, hypertension, and hypertriglyceridemia is absent. FunctionSHIP2_HUMAN Phosphatidylinositol (PtdIns) phosphatase that specifically hydrolyzes the 5-phosphate of phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3) to produce PtdIns(3,4)P2, thereby negatively regulating the PI3K (phosphoinositide 3-kinase) pathways. Plays a central role in regulation of PI3K-dependent insulin signaling, although the precise molecular mechanisms and signaling pathways remain unclear. While overexpression reduces both insulin-stimulated MAP kinase and Akt activation, its absence does not affect insulin signaling or GLUT4 trafficking. Confers resistance to dietary obesity. May act by regulating AKT2, but not AKT1, phosphorylation at the plasma membrane. Part of a signaling pathway that regulates actin cytoskeleton remodeling. Required for the maintenance and dynamic remodeling of actin structures as well as in endocytosis, having a major impact on ligand-induced EGFR internalization and degradation. Participates in regulation of cortical and submembraneous actin by hydrolyzing PtdIns(3,4,5)P3 thereby regulating membrane ruffling. Regulates cell adhesion and cell spreading. Required for HGF-mediated lamellipodium formation, cell scattering and spreading. Acts as a negative regulator of EPHA2 receptor endocytosis by inhibiting via PI3K-dependent Rac1 activation. Acts as a regulator of neuritogenesis by regulating PtdIns(3,4,5)P3 level and is required to form an initial protrusive pattern, and later, maintain proper neurite outgrowth. Acts as a negative regulator of the FC-gamma-RIIA receptor (FCGR2A). Mediates signaling from the FC-gamma-RIIB receptor (FCGR2B), playing a central role in terminating signal transduction from activating immune/hematopoietic cell receptor systems. Involved in EGF signaling pathway. Upon stimulation by EGF, it is recruited by EGFR and dephosphorylates PtdIns(3,4,5)P3. Plays a negative role in regulating the PI3K-PKB pathway, possibly by inhibiting PKB activity. Down-regulates Fc-gamma-R-mediated phagocytosis in macrophages independently of INPP5D/SHIP1. In macrophages, down-regulates NF-kappa-B-dependent gene transcription by regulating macrophage colony-stimulating factor (M-CSF)-induced signaling. May also hydrolyze PtdIns(1,3,4,5)P4, and could thus affect the levels of the higher inositol polyphosphates like InsP6.[3] [4] [5] [6] [7] [8] [9] [10] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSterile alpha motif (Sam) domains are protein interaction modules that are implicated in many biological processes mainly via homo- and heterodimerization. It has been recently reported that the lipid phosphatase Ship2 regulates endocytosis of the EphA2 receptor, a process that has been investigated as a possible route to reduce tumor malignancy. A heterotypic Sam-Sam domain interaction is mediating this process. Here, we report NMR and ITC (isothermal titration calorimetry) studies on the Sam domain of Ship2 revealing its three-dimensional structure and its possible mode of interaction with the Sam domain from the EphA2 receptor. These studies have also resulted in the identification of a minimal peptide region of Ship2 that retains binding affinity for the Sam domain of the EphA2 receptor. Hence, this peptide and the detection of key structural elements important for EphA2 receptor endocytosis provide possible ways for the development of novel small molecule antagonists with potential anticancer activity. NMR Studies of a Heterotypic Sam-Sam Domain Association: The Interaction between the Lipid Phosphatase Ship2 and the EphA2 Receptor(,).,Leone M, Cellitti J, Pellecchia M Biochemistry. 2008 Nov 8. PMID:18991394[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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