Activated Cdc42-bound IQGAP1 determines the cellular endocytic site

Toshihide Kimura, Mami Yamaoka, Shigeki Taniguchi, Mitsuhiro Okamoto, Masahiro Takei, Tomomi Ando, Akihiro Iwamatsu, Takashi Watanabe, Kozo Kaibuchi, Toshimasa Ishizaki, Ichiro Niki

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


Recruitment of specific molecules to a specific membrane site is essential for communication between specialized membranous organelles. In the present study, we identified IQGAP1 as a novel GDP-bound-Rab27a-interacting protein. We found that IQGAP1 interacts with GDP-bound Rab27a when it forms a complex with GTP-bound Cdc42. We also found that IQGAP1 regulates the endocytosis of insulin secretory membranes. Silencing of IQGAP1 inhibits both endocytosis and the glucose-induced redistribution of endocytic machinery, including Rab27a and its binding protein coronin 3. These processes can also be inhibited by disruption of the trimeric complex with dominant negative IQGAP1 and Cdc42. These results indicate that activation of Cdc42 in response to the insulin secretagogue glucose recruits endocytic machinery to IQGAP1 at the cell periphery and regulates endocytosis at this membrane site.

Original languageEnglish
Pages (from-to)4834-4843
Number of pages10
JournalMolecular and Cellular Biology
Issue number24
Publication statusPublished - 12-2013
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology


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