A Protein Tyrosine Phosphatase Inhibitor, Pervanadate, Inhibits Angiotensin Ⅱ-Induced β-Arrestin Cleavage
2009
Jang, S.H. (Daegu University, Gyeongsan, Republic of Korea) | Hwang, S.A. (Daegu University, Gyeongsan, Republic of Korea) | Kim, M.J. (Daegu University, Gyeongsan, Republic of Korea) | Yun, S.H. (Daegu Science High School, Daegu, Republic of Korea) | Kim, M.S. (Daegu Science High School, Daegu, Republic of Korea) | Karnik, Sadashiva S. (Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA) | Lee, C.W. (Daegu University, Gyeongsan, Republic of Korea), E-mail: [email protected]
β-Arrestins turn off G protein-mediated signals and initiate distinct G protein-independent signaling pathways. We previously demonstrated that angiotensin AT₁ receptor-bound β-arrestin 1 is cleaved after Phe∨388 upon angiotensin Ⅱ stimulation. The mechanism and signaling pathway of angiotensin Ⅱ-induced β-arrestin cleavage remain largely unknown. Here, we show that protein Tyr phosphatase activity is involved in the regulation of β-arrestin 1 cleavage. Tagging of green fluorescent protein (GFP) either to the N-terminus or C-terminus of β-arrestin 1 induced conformational changes and the cleavage of β-arrestin 1 without angiotensin AT₁ receptor activation. Orthovanadate and molybdate, inhibitors of protein Tyr phosphatase, attenuated the cleavage of C-terminal GFP-tagged β-arrestin 1 in vitro. The inhibitory effects of okadaic acid and pyrophosphate, which are inhibitors of protein Ser/Thr phosphatase, were less than those of protein Tyr phosphatase inhibitors. Cell-permeable pervanadate inhibited angiotensin Ⅱ-induced cleavage of β-arrestin 1 in COS-1 cells. Our findings suggest that Tyr phosphorylation signaling is involved in the regulation of angiotensin Ⅱ-induced β-arrestin cleavage.
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