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| Subject Categories:
Structural Biology
| Signal Transduction
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The EMBO Journal
(2004) 23, 4413–4422, doi:10.1038/sj.emboj.7600442 Published online 14 October 2004
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| Regulation of Bin1 SH3 domain binding by phosphoinositides |
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Chie Kojima1, 2, Ari Hashimoto1, Izumi Yabuta3, Mayumi Hirose1, Shigeru Hashimoto1, Yasunori Kanaho4, Hideki Sumimoto5, Takahisa Ikegami3 and Hisataka Sabe1, 2
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1 Department of Molecular Biology, Osaka Bioscience Institute, Suita, Japan
2 Graduate School of Biostudies, Kyoto University, Sakyo-ku, Japan
3 Laboratory of Structural Proteomics, Institute for Protein Research, Osaka University, Suita, Japan
4 Department of Pharmacology, Tokyo Metropolitan Institute of Medical Science, Bunkyo-ku, Japan
5 Department of Biochemistry and Molecular Biology, Medical Institute for Bioregulation, Kyushu University, Higashi-ku, Japan
To whom correspondence should be addressed
Hisataka Sabe, Department of Molecular Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan. Tel.: +81 6 6872 4814; Fax: +81 6 6871 6686; E-mail: sabe@obi.or.jp
Received 19 May 2004; Accepted 20 September 2004; Published online 14 October 2004.
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| Abstract |
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Bin1/M-amphiphysin-II is an amphiphysin-II isoform highly expressed in transverse tubules of adult striated muscle and is implicated in their biogenesis. Bin1 contains a basic unique amino-acid sequence, Exon10, which interacts with certain phosphoinositides such as phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2), to localize to membranes. Here we found that Exon10 also binds to the src homology 3 (SH3) domain of Bin1 itself, and hence blocks the binding of the SH3 domain to its canonical PxxP ligands, including dynamin. This blockage was released by addition of PI(4,5)P2 in vitro or in cells overexpressing phosphatidylinositol 4-phosphate 5-kinase. The Exon10-binding interface of the Bin1 SH3 domain largely overlapped with its PxxP-binding interface. We also show that the PLC pleckstrin homology domain, another PI(4,5)P2-binding module, cannot substitute for Exon10 in Bin1 function in transverse tubule formation, and suggest the importance of the dual biochemical properties of Exon10 in myogenesis. Our results exemplify a novel mechanism of SH3 domain regulation, and suggest that the SH3-mediated protein–protein interactions of Bin1 are regulated by Exon10 so that it may only occur when Bin1 localizes to certain submembrane areas. |
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| Keywords: Bin1, phosphoinositide, protein–protein interaction, SH3 domain, transverse tubule |
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