Phosphorylation of WAVE Downstream of Mitogen-activated Protein Kinase Signaling*
- From the Department of Biochemistry, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108, Japan and the ‡Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake, Kyoto 606-01, Japan
Abstract
WAVE is a Wiskott-Aldrich syndrome protein (WASP)-family protein that functions in membrane-ruffling formation induced by Rac, a Rho family small GTPase. Here we report that WAVE is a phosphoprotein whose phosphorylation increases in response to various external stimuli that activate mitogen-activated protein (MAP) kinase signaling. When Swiss 3T3 cells are stimulated with platelet-derived growth factor, electrophoretic mobility shift occurs to WAVE, which reflects hyperphosphorylation. This is perfectly inhibited by the addition of PD98059, a specific inhibitor of MAP kinase kinase. Indeed, the ectopic expression of an activated mutant of MAP kinase kinase induces WAVE mobility shift. When MAP kinase activation is suppressed by PD98059, the intensity of platelet-derived growth factor-induced membrane ruffling is greatly reduced. In various cancer cell lines, the amount of WAVE mobility shift was found to increase significantly, suggesting the importance of WAVE hyperphosphorylation in the formation of membrane ruffles and oncogenic transformation.
Footnotes
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↵* This study was supported in part by a grant-in-aid for cancer research from the Ministry of Education, Science, and Culture of Japan and by a grant-in-aid for the Research for the Future Program from the Japan Society for the Promotion of Science.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵§ To whom correspondence should be addressed: Dept. of Biochemistry, Inst. of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108, Japan. Tel.: 81-3-5449-5510; Fax: 81-3-5449-5417; E-mail: takenawa@ims.u-tokyo.ac.jp.
- Abbreviations:
- WASP
-
Wiskott-Aldrich syndrome protein
- GST
-
glutathioneS-transferase
- LPA
-
lysophosphatidic acid
- MAP
-
mitogen-activated protein
- MEK
-
MAP kinase kinase
- PDGF
-
platelet-derived growth factor
- BHK
-
baby hamster kidney
- HA
-
hemagglutinin
- MDCK
-
Madin-Darby canine kidney
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- Received June 15, 1999.
- The American Society for Biochemistry and Molecular Biology, Inc.
