tyrosine phosphorylation of rac1 a role in regulation of cell spreading酪氨酸的磷酸化rac1作用在调节细胞扩散.pdf

Tyrosine Phosphorylation of Rac1: A Role in Regulation of Cell Spreading 1 2 3 4 1,5 Fumin Chang , Christopher Lemmon , Daniel Lietha , Michael Eck , Lewis Romer * 1 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America, 2 Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America, 3 Spanish National Cancer Research Centre (CNIO), Madrid, Spain, 4 Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School and Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America, 5 Departments of Cell Biology, Biomedical Engineering, Pediatrics, and the Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America 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 bPIX, 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