title: Interaction of p190A RhoGAP with eIF3A and Other Translation Preinitiation Factors Suggests a Role in Protein Biosynthesis.
abstract: The negative regulator of Rho family GTPases, p190A RhoGAP, is one of six mammalian proteins harboring so-called FF motifs. To explore the function of these and other p190A segments, we identified interacting proteins by tandem mass spectrometry. Here we report that endogenous human p190A, but not its 50% identical p190B paralog, associates with all 13 eIF3 subunits and several other translational preinitiation factors. The interaction involves the first FF motif of p190A and the winged helix/PCI domain of eIF3A, is enhanced by serum stimulation and reduced by phosphatase treatment. The p190A/eIF3A interaction is unaffected by mutating phosphorylated p190A-Tyr308, but disrupted by a S296A mutation, targeting the only other known phosphorylated residue in the first FF domain. The p190A-eIF3 complex is distinct from eIF3 complexes containing S6K1 or mammalian target of rapamycin (mTOR), and appears to represent an incomplete preinitiation complex lacking several subunits. Based on these findings we propose that p190A may affect protein translation by controlling the assembly of functional preinitiation complexes. Whether such a role helps to explain why, unique among the large family of RhoGAPs, p190A exhibits a significantly increased mutation rate in cancer remains to be determined.
authors.affiliation: From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129.
authors.forename: Prasanna
authors.initials: P
authors.lastname: Parasuraman
authors.affiliation: From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129.
authors.forename: Peter
authors.initials: P
authors.lastname: Mulligan
authors.affiliation: From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129.
authors.forename: James A
authors.initials: JA
authors.lastname: Walker
authors.affiliation: From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129.
authors.forename: Bihua
authors.initials: B
authors.lastname: Li
authors.affiliation: From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129.
authors.forename: Myriam
authors.initials: M
authors.lastname: Boukhali
authors.affiliation: From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129.
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Haas
authors.affiliation: From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129 abernards@partners.org.
authors.forename: Andre
authors.identifier: 0000-0001-6590-2337
authors.initials: A
authors.lastname: Bernards
mesh_terms: D000818:Animals; D002846:Chromatography, Affinity; D039621:Eukaryotic Initiation Factor-3 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D020125:Mutation, Missense; D041681:NIH 3T3 Cells; D011485:Protein Binding; D014176:Protein Biosynthesis; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: C074560:ARHGAP35 protein, human; C105988:EIF3A protein, human; D039621:Eukaryotic Initiation Factor-3; D020662:Guanine Nucleotide Exchange Factors; D012097:Repressor Proteins
keywords: GTPase activating protein (GAP); Rho (Rho GTPase); cell biology; mass spectrometry (MS); protein biosynthesis; protein complexes; protein domains; translation ini; translation initiation factor; translational initiation