The small GTPase Cdc42 modulates the number of exocytosis-competent dense-core vesicles in PC12 cells

Mai Sato, Tetsuya Kitaguchi, Rika Numano, Kazuya Ikematsu, Masaki Kakeyama, Masayuki Murata, Ken Sato, Takashi Tsuboi

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Although the small GTPase Rho family Cdc42 has been shown to facilitate exocytosis through increasing the amount of hormones released, the precise mechanisms regulating the quantity of hormones released on exocytosis are not well understood. Here we show by live cell imaging analysis under TIRF microscope and immunocytochemical analysis under confocal microscope that Cdc42 modulated the number of fusion events and the number of dense-core vesicles produced in the cells. Overexpression of a wild-type or constitutively-active form of Cdc42 strongly facilitated high-KCl-induced exocytosis from the newly recruited plasma membrane vesicles in PC12 cells. By contrast, a dominant-negative form of Cdc42 inhibited exocytosis from both the newly recruited and previously docked plasma membrane vesicles. The number of intracellular dense-core vesicles was increased by the overexpression of both a wild-type and constitutively-active form of Cdc42. Consistently, activation of Cdc42 by overexpression of Tuba, a Golgi-associated guanine nucleotide exchange factor for Cdc42 increased the number of intracellular dense-core vesicles, whereas inhibition of Cdc42 by overexpression of the Cdc42/Rac interactive binding domain of neuronal Wiskott-Aldrich syndrome protein decreased the number of them. These findings suggest that Cdc42 facilitates exocytosis by modulating both the number of exocytosis-competent dense-core vesicles and the production of dense-core vesicles in PC12 cells.

Original languageEnglish
Pages (from-to)417-421
Number of pages5
JournalBiochemical and Biophysical Research Communications
Volume420
Issue number2
DOIs
Publication statusPublished - 2012 Apr 6
Externally publishedYes

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Keywords

  • Cdc42
  • Dense-core vesicle
  • Exocytosis
  • GTPase
  • Live cell imaging
  • Neuroendocrine cells

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Cell Biology
  • Molecular Biology

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