Protein phosphatase 1 alpha associates with protein tyrosine phosphatase-PEST inducing dephosphorylation of phospho-serine 39

作者：Nakamura Kana; Palmer Helen E F; Ozawa Tomoko^*; Mashima Keisuke

来源：Journal of Biochemistry, 2010, 147(4): 493-500.

DOI：10.1093/jb/mvp191

• Dephosphorylation
• PP1 alpha
• PTP activity
• PTP-PEST
• yeast two-hybrid system

Protein tyrosine phosphatase (PTP)-PEST is expressed in a wide variety of several cell types and is an efficient regulator of cell adhesion, spreading and migration. PTP-PEST-associating molecules are important in elucidating the function of PTP-PEST. Herein, we have identified protein phosphatase 1 alpha (PP1 alpha) as a novel PTP-PEST binding protein, and then we aimed to determine how PP1 alpha contributes to the phosphorylation at Ser39 of PTP-PEST, whose phosphorylation suppresses PTP-PEST enzymatic activity. The HEK 293 cells overexpressing exogenous PTP-PEST were stimulated by 12-O-tetradecanoylphorbol 13-acetate (TPA) and the phosphorylation of PTP-PEST at Ser39 was evaluated using an anti-phospho-Ser39 PTP-PEST specific antibody (anti-pS39-PEST Ab). It was demonstrated that the phosphorylation at Ser39 detected by anti-pS39-PEST Ab was dependent on TPA treatment and a significant inverse correlation between the PTP activity of PTP-PEST and anti-pS39-PEST Ab-immunoreactive band intensity. The phosphorylation of Ser39 was suppressed by co-transfection of a plasmid encoding wild-type PP1 alpha, but not by that of the dominant-negative PP1 alpha mutant. Furthermore, TPA-induced phosphorylation could take place in PTP-PEST catalytic domain, but the phosphorylation of PTP-PEST catalytic domain could not be abrogated by co-transfection of a plasmid expressing wild-type PP1 alpha. In conclusion, PP1 alpha associates with the non-catalytic domain of PTP-PEST and regulates PTP activity via dephosphorylation of phospho-Ser39.

• 出版日期2010-4