title: Tyrosine phosphorylation of Rac1: a role in regulation of cell spreading.
abstract: Rac1 influences a multiplicity of vital cellular- and tissue-level control functions, making it an important candidate for targeted therapeutics. The activity of the Rho family member Cdc42 has been shown to be modulated by tyrosine phosphorylation at position 64. We therefore investigated consequences of the point mutations Y64F and Y64D in Rac1. Both mutations altered cell spreading from baseline in the settings of wild type, constitutively active, or dominant negative Rac1 expression, and were accompanied by differences in Rac1 targeting to focal adhesions. Rac1-Y64F displayed increased GTP-binding, increased association with βPIX, and reduced binding with RhoGDI as compared with wild type Rac1. Rac1-Y64D had less binding to PAK than Rac1-WT or Rac1-64F. In vitro assays demonstrated that Y64 in Rac1 is a target for FAK and Src. Taken together, these data suggest a mechanism for the regulation of Rac1 activity by non-receptor tyrosine kinases, with consequences for membrane extension.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Fumin
authors.initials: F
authors.lastname: Chang
authors.forename: Christopher
authors.initials: C
authors.lastname: Lemmon
authors.forename: Daniel
authors.initials: D
authors.lastname: Lietha
authors.forename: Michael
authors.initials: M
authors.lastname: Eck
authors.forename: Lewis
authors.initials: L
authors.lastname: Romer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology; D004926:Escherichia coli / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D022001:Focal Adhesions; D006801:Humans; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D009479:Neuropeptides / Q000235:genetics* / Q000378:metabolism*; D010766:Phosphorylation; D017354:Point Mutation; D011485:Protein Binding; D014162:Transfection; D014443:Tyrosine / Q000737:chemistry / Q000378:metabolism*; D020764:cdc42 GTP-Binding Protein / Q000235:genetics; D020744:rac GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein
chemical_list: D009479:Neuropeptides; C484602:Rac1 protein, mouse; D014443:Tyrosine; D051416:Focal Adhesion Protein-Tyrosine Kinases; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein