title: RhoJ interacts with the GIT-PIX complex and regulates focal adhesion disassembly.
abstract: RhoJ is a Rho GTPase expressed in endothelial cells and tumour cells, which regulates cell motility, invasion, endothelial tube formation and focal adhesion numbers. This study aimed to further delineate the molecular function of RhoJ. Using timelapse microscopy RhoJ was found to regulate focal adhesion disassembly; small interfering RNA (siRNA)-mediated knockdown of RhoJ increased focal adhesion disassembly time, whereas expression of an active mutant (daRhoJ) decreased it. Furthermore, daRhoJ co-precipitated with the GIT-PIX complex, a regulator of focal adhesion disassembly. An interaction between daRhoJ and GIT1 was confirmed using yeast two-hybrid experiments, and this depended on the Spa homology domain of GIT1. GIT1, GIT2, β-PIX (also known as ARHGEF7) and RhoJ all colocalised in focal adhesions and depended on each other for their recruitment to focal adhesions. Functionally, the GIT-PIX complex regulated endothelial tube formation, with knockdown of both GIT1 and GIT2, or β-PIX phenocopying RhoJ knockdown. RhoJ-knockout mice showed reduced tumour growth and diminished tumour vessel density, identifying a role for RhoJ in mediating tumour angiogenesis. These studies give new insight into the molecular function of RhoJ in regulating cell motility and tumour vessel formation.
authors.affiliation: School of Immunity and Infection, Institute for Biomedical Research, The Medical School, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Eleanor
authors.initials: E
authors.lastname: Wilson
authors.affiliation: School of Immunity and Infection, Institute for Biomedical Research, The Medical School, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Leszczynska
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Natalie S
authors.initials: NS
authors.lastname: Poulter
authors.affiliation: School of Immunity and Infection, Institute for Biomedical Research, The Medical School, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Francesca
authors.initials: F
authors.lastname: Edelmann
authors.affiliation: School of Immunity and Infection, Institute for Biomedical Research, The Medical School, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Salisbury
authors.affiliation: School of Immunity and Infection, Institute for Biomedical Research, The Medical School, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Noy
authors.affiliation: School of Immunity and Infection, Institute for Biomedical Research, The Medical School, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bacon
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Joshua Z
authors.initials: JZ
authors.lastname: Rappoport
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: John K
authors.initials: JK
authors.lastname: Heath
authors.affiliation: School of Immunity and Infection, Institute for Biomedical Research, The Medical School, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Roy
authors.initials: R
authors.lastname: Bicknell
authors.affiliation: School of Immunity and Infection, Institute for Biomedical Research, The Medical School, University of Birmingham, Birmingham B15 2TT, UK v.heath@bham.ac.uk.
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Heath
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology; D022001:Focal Adhesions / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010750:Phosphoproteins / Q000378:metabolism; D064067:Rho Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D015398:Signal Transduction; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; C485647:GIT1 protein, human; C430213:GIT2 protein, human; D020690:GTPase-Activating Proteins; C120766:Git1 protein, mouse; C120767:Git2 protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; C576609:PIX protein, human; D010750:Phosphoproteins; D064067:Rho Guanine Nucleotide Exchange Factors; C485944:Rhoj protein, mouse; D020558:GTP Phosphohydrolases; C417188:RHOJ protein, human; D020741:rho GTP-Binding Proteins
keywords: Angiogenesis; Focal adhesion; GIT; PIX; RhoJ