title: Rnd3-induced cell rounding requires interaction with Plexin-B2.
abstract: Rnd proteins are atypical members of the Rho GTPase family that induce actin cytoskeletal reorganization and cell rounding. Rnd proteins have been reported to bind to the intracellular domain of several plexin receptors, but whether plexins contribute to the Rnd-induced rounding response is not known. Here we show that Rnd3 interacts preferentially with plexin-B2 of the three plexin-B proteins, whereas Rnd2 interacts with all three B-type plexins, and Rnd1 shows only very weak interaction with plexin-B proteins in immunoprecipitations. Plexin-B1 has been reported to act as a GAP for R-Ras and/or Rap1 proteins. We show that all three plexin-B proteins interact with R-Ras and Rap1, but Rnd proteins do not alter this interaction or R-Ras or Rap1 activity. We demonstrate that plexin-B2 promotes Rnd3-induced cell rounding and loss of stress fibres, and enhances the inhibition of HeLa cell invasion by Rnd3. We identify the amino acids in Rnd3 that are required for plexin-B2 interaction, and show that mutation of these amino acids prevents Rnd3-induced morphological changes. These results indicate that plexin-B2 is a downstream target for Rnd3, which contributes to its cellular function.
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK.
authors.forename: Brad
authors.initials: B
authors.lastname: McColl
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK.
authors.forename: Ritu
authors.initials: R
authors.lastname: Garg
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK.
authors.forename: Philippe
authors.initials: P
authors.lastname: Riou
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK.
authors.forename: Kirsi
authors.initials: K
authors.lastname: Riento
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK anne.ridley@kcl.ac.uk.
authors.forename: Anne J
authors.identifier: 0000-0001-8186-5708
authors.initials: AJ
authors.lastname: Ridley
mesh_terms: D000818:Animals; D019556:COS Cells; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000378:metabolism*; D048430:Cell Shape; D002522:Chlorocebus aethiops; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D000072417:Protein Domains; D020668:rap GTP-Binding Proteins / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D015815:Cell Adhesion Molecules; D009419:Nerve Tissue Proteins; C091529:plexin; C508705:RND3 protein, human; D020668:rap GTP-Binding Proteins; D018631:ras Proteins; D020741:rho GTP-Binding Proteins
keywords: Actin cytoskeleton; Cell shape; Plexin; Rho GTPase