title: The PH domain of Ras-GAP is sufficient for in vitro binding to beta gamma subunits of heterotrimeric G proteins.
abstract: 1. The noncatalytic domain of Ras-GAP can affect signaling through G protein-coupled receptors by a poorly understood mechanism. 2. In this study, fusion proteins containing elements of the noncatalytic domain of ras-GAP were examined for their ability to bind beta gamma subunits of heterotrimeric G proteins and phosphotyrosine-containing polypeptides. 3. Our results demonstrate that purified beta gamma dimers associated with bacterially expressed GAP proteins and that this association does not require SH2 or SH3 domains but is dependent on the presence of the GAP pleckstrin-homology (PH) domain. In contrast, only the SH2 domains are necessary for binding to tyrosine phosphorylated proteins. 4. These findings raise the possibility that heterotrimeric G proteins might affect functioning of ras-like proteins through beta gamma subunits acting on their regulatory molecules.
authors.affiliation: Laboratory of Cellular Development and Oncology, National Institute of Dental Research, Bethesda, Maryland, USA.
authors.forename: N
authors.initials: N
authors.lastname: Xu
authors.forename: O
authors.initials: O
authors.lastname: Coso
authors.forename: D
authors.initials: D
authors.lastname: Mahadevan
authors.forename: A
authors.initials: A
authors.lastname: De Blasi
authors.forename: P K
authors.initials: PK
authors.lastname: Goldsmith
authors.forename: W F
authors.initials: WF
authors.lastname: Simonds
authors.forename: J S
authors.initials: JS
authors.lastname: Gutkind
mesh_terms: D001665:Binding Sites; D001798:Blood Proteins / Q000737:chemistry; D003001:Cloning, Molecular; D004926:Escherichia coli; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D005982:Glutathione Transferase / Q000096:biosynthesis; D006801:Humans; D046911:Macromolecular Substances; D010750:Phosphoproteins; D019000:Phosphotyrosine; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D015183:Restriction Mapping; D020703:ras GTPase-Activating Proteins; D018909:src Homology Domains
chemical_list: D001798:Blood Proteins; D020690:GTPase-Activating Proteins; D046911:Macromolecular Substances; D010750:Phosphoproteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; C039077:platelet protein P47; D020703:ras GTPase-Activating Proteins; D019000:Phosphotyrosine; D005982:Glutathione Transferase; D019204:GTP-Binding Proteins