cortactin tyrosine phosphorylation promotes its deacetylation and inhibits cell spreadingcortactin酪氨酸磷酸化促进其脱乙酰作用和抑制细胞扩散.pdf

Cortactin Tyrosine Phosphorylation Promotes Its Deacetylation and Inhibits Cell Spreading ´ Eugenia Meiler, Elvira Nieto-Pelegrın, Narcisa Martinez-Quiles* ´ Departamento de Microbiologıa II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain Abstract Background: Cortactin is a classical Src kinase substrate that participates in actin cytoskeletal dynamics by activating the Arp2/3 complex and interacting with other regulatory proteins, including FAK. Cortactin has various domains that may contribute to the assembly of different protein platforms to achieve process specificity. Though the protein is known to be regulated by post-translational modifications such as phosphorylation and acetylation, how tyrosine phosphorylation regulates cortactin activity is poorly understood. Since the basal level of tyrosine phosphorylation is low, this question must be studied using stimulated cell cultures, which are physiologically relevant but unreliable and difficult to work with. In fact, their unreliability may be the cause of some contradictory findings about the dynamics of tyrosine phosphorylation of cortactin in different processes. Methodology/Principal Findings: In the present study, we try to overcome these problems by using a Functional Interaction Trap (FIT) system, which involves cotransfecting cells with a kinase (Src) and a target protein (cortactin), both of which are fused to complementary leucine-zipper domains. The FIT system allowed us to control precisely the tyrosine phosphorylation of cortactin and explore its relationship with cortactin acetylation. Conclusions/Significance: Using this system, we provide defini