The biological roles of small GTPases and interacting proteins in plants

Hirofumi Uchimiya, Toyoaki Anai, Evalour T. Aspuria, Minami Matsui, Akihiko Nakano, Takashi Ueda

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Extensive studies on the molecular mechanisms of vesicular trafficking have revealed that molecules involved in this cellular function are remarkably well conserved from yeast to higher plants. However, it is not clear at all how a variety of organisms maintain the individual divergent systems using the common machinery of vesicular traffic. We have been attempting to understand the roles and regulatory mechanisms of vesicular traffic in plants through the study of Rab/Ypt GTPases. Ara proteins are Rab/Ypt homologues of Arabidopsis, which are implicated in the regulation of vesicular traffic. Their biochemical properties are similar to those of the Rab/Ypt proteins from animal and yeast cells. The overexpression of ARA2 or ARA4 causes pleiotropic morphological abnormalities in the transgenic tobacco plants. The GTPase cycle of Ara proteins has to be strictly controlled for their proper functions. We have identified two classes of regulator molecules of Ara2 and Ara4. One is the GTPase activating protein (GAP), and the other is the GDP dissociation inhibitor (GDI). GAP has been identified as an activity accelerating the hydrolysis of GTP by Ara2 or Ara4. GDI (AtGDH) has been isolated as a molecule interacting with Ara4 using a novel method for detecting interactions between foreign molecules in yeast. Further studies on the interacting molecules should unveil the regulatory system of and signal transduction pathway via Ara proteins.

Original languageEnglish
Pages (from-to)257-260
Number of pages4
JournalJournal of Plant Research
Issue number2
Publication statusPublished - Jun 1998
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Plant Science


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