QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Eda, M. Articles by Narumiya, S. Search for Related Content PubMed PubMed Citation Articles by Eda, M. Articles by Narumiya, S.

Rho-dependent transfer of Citron-kinase to the cleavage furrow of dividing cells

Masatoshi Eda¹, Shigenobu Yonemura², Takayuki Kato¹, Naoki Watanabe^1,*, Toshimasa Ishizaki¹, Pascal Madaule^1, and Shuh Narumiya^1,

¹ Department of Pharmacology, Kyoto University Faculty of Medicine, Sakyo, Kyoto 606-8501, Japan
² Department of Cell Biology, Kyoto University Faculty of Medicine, Sakyo, Kyoto 606-8501, Japan
^* Present address: Department of Cell Biology, Harvard Medical School, 250 Longwood Ave. SGM 520, Boston, MA 02115, USA
Present address: Récepteurs et signalisation des interleukines, INSERM U 461, Faculté de Pharmacie de l’Université d’Orsay, 5 rue Jean Baptiste Clément, 92296 Châtenay-Malabry, France

Author for correspondence (e-mail: snaru{at}mfour.med.kyoto-u.ac.jp)

Accepted June 7, 2001

Citron-kinase (Citron-K) is a Rho effector working in cytokinesis. It is enriched in cleavage furrow, but how Rho mobilizes Citron-K remains unknown. Using anti-Citron antibody and a Citron-K Green Fluorescence Protein (GFP)-fusion, we monitored its localization in cell cycle. We have found: (1) Citron-K is present as aggregates in interphase cells, disperses throughout the cytoplasm in prometaphase, translocates to cell cortex in anaphase and accumulates in cleavage furrow in telophase; (2) Rho colocalizes with Citron-K in the cortex of ana- to telophase cells and the two proteins are concentrated in the cleavage furrow and to the midbody; (3) inactivation of Rho by C3 exoenzyme does not affect the dispersion of Citron-K in prometaphase, but prevented its transfer to the cell cortex, and Citron-K stays in association with the midzone spindles of C3 exoenzyme-treated cells. To clarify further the mechanism of the Rho-mediated transfer and concentration of Citron-K in cleavage furrow, we expressed active Val14RhoA in interphase cells expressing GFP-Citron-K. Val14RhoA expression transferred Citron-K to the ventral cortex of interphase cells, where it formed band-like structures in a complex with Rho. This structure was localized at the same plane as actin stress fibers, and they exclude each other. Disruption of F-actin abolished the band and dispersed the Citron-K-Rho-containing patches throughout the cell cortex. Similarly, in dividing cells, a structure composed of Rho and Citron-K in cleavage furrow excludes cortical actin cytoskeleton, and disruption of F-actin disperses Citron-K throughout the cell cortex. These results suggest that Citron-K is a novel type of a passenger protein, which is dispersed to the cytoplasm in prometaphase and associated with midzone spindles by a Rho-independent signal. Rho is then activated, binds to Citron-K and translocates it to cell cortex, where the complex is then concentrated in the cleavage furrow by the action of actin cytoskeleton beneath the equator of dividing cells.

Key words: Citron, Rho, Cytokinesis, Actin cytoskeleton, Cleavage furrow

This article has been cited by other articles:

				D. A. Guertin, S. Trautmann, and D. McCollum Cytokinesis in Eukaryotes Microbiol. Mol. Biol. Rev., June 1, 2002; 66(2): 155 - 178. [Abstract] [Full Text] [PDF]