WAVE2 activates the actin-related protein (Arp) 2/3 complex for Rac-induced actin polymerization during lamellipodium formation and exists as a large WAVE2 protein complex with Sra1/PIR121, Nap1, Abi1, and HSPC300. IRSp53 binds to both Rac and Cdc42 and is proposed to link Rac to WAVE2. We found that the knockdown of IRSp53 by RNA interference decreased lamellipodium formation without a decrease in the amount of WAVE2 complex. Localization of WAVE2 at the cell periphery was retained in IRSp53 knockdown cells. Moreover, activated Cdc42 but not Rac weakened the association between WAVE2 and IRSp53. When we measured Arp2/3 activation in vitro, the WAVE2 complex isolated from the membrane fraction of cells was fully active in an IRSp53-dependent manner but WAVE2 isolated from the cytosol was not. Purified WAVE2 and purified WAVE2 complex were activated by IRSp53 in a Rac-dependent manner with PIP3-containing liposomes. Therefore, IRSp53 optimizes the activity of the WAVE2 complex in the presence of activated Rac and PIP3.
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22 May 2006
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May 15 2006
Optimization of WAVE2 complex–induced actin polymerization by membrane-bound IRSp53, PIP3, and Rac
Shiro Suetsugu,
Shiro Suetsugu
1Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
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Shusaku Kurisu,
Shusaku Kurisu
1Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
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Tsukasa Oikawa,
Tsukasa Oikawa
1Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
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Daisuke Yamazaki,
Daisuke Yamazaki
1Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
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Atsushi Oda,
Atsushi Oda
3Laboratory of Environmental Biology, Department of Preventive Medicine, Hokkaido University School of Medicine, Kitaku, Sapporo 060-8638, Japan
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Tadaomi Takenawa
Tadaomi Takenawa
1Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
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Shiro Suetsugu
1Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
Shusaku Kurisu
1Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
Tsukasa Oikawa
1Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
Daisuke Yamazaki
1Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
Atsushi Oda
3Laboratory of Environmental Biology, Department of Preventive Medicine, Hokkaido University School of Medicine, Kitaku, Sapporo 060-8638, Japan
Tadaomi Takenawa
1Department of Biochemistry, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
2Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
Correspondence to Tadaomi Takenawa: [email protected]
Abbreviations used in this paper: Arp, actin-related protein; CA, constitutively active; DN, dominant negative; IMD, IRSp53/missing in metastasis homology domain; IRTKS, insulin receptor tyrosine kinase substrate; MEF, mouse embryonic fibroblast; PC, phosphatidylcholine; PI, phosphatidylinositol; SH3, Src homology 3; N-WASP, neural WASP; RCB, Rac binding; WASP, Wiskott-Aldrich syndrome protein; WHD, WAVE homology domain.
Received:
September 12 2005
Accepted:
April 13 2006
Online ISSN: 1540-8140
Print ISSN: 0021-9525
The Rockefeller University Press
2006
J Cell Biol (2006) 173 (4): 571–585.
Article history
Received:
September 12 2005
Accepted:
April 13 2006
Citation
Shiro Suetsugu, Shusaku Kurisu, Tsukasa Oikawa, Daisuke Yamazaki, Atsushi Oda, Tadaomi Takenawa; Optimization of WAVE2 complex–induced actin polymerization by membrane-bound IRSp53, PIP3, and Rac . J Cell Biol 22 May 2006; 173 (4): 571–585. doi: https://doi.org/10.1083/jcb.200509067
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