JCB logo
Accuri Cytometers
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
Published online 5 March 2001. doi:10.1083/jcb.152.5.1019
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 496K)
Right arrow PPT slides of all figures
Right arrow Supplemental Material Index
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Fu, Y.
Right arrow Articles by Yang, Z.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Fu, Y.
Right arrow Articles by Yang, Z.
Related Collections
Right arrowRelated Article
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

© The Rockefeller University Press, 0021-9525/2001//1019 $5.00
The Journal of Cell Biology, Volume 152, Number 5, , 2001 1019-1032

Original Article

ROP Gtpase–Dependent Dynamics of Tip-Localized F-Actin Controls Tip Growth in Pollen Tubes



Ying Fua, Guang Wua, and Zhenbiao Yanga

a Department of Botany and Plant Sciences, University of California, Riverside, California 92521
Department of Botany and Plant Sciences, University of California, Riverside, CA 92521.(909) 787-4437(909) 787-7351

zhenbiao.yang{at}ucr.edu

Tip-growing pollen tubes provide a useful model system to study polar growth. Although roles for tip-focused calcium gradient and tip-localized Rho-family GTPase in pollen tube growth is established, the existence and function of tip-localized F-actin have been controversial. Using the green fluorescent protein–tagged actin-binding domain of mouse talin, we found a dynamic form of tip-localized F-actin in tobacco pollen tubes, termed short actin bundles (SABs). The dynamics of SABs during polar growth in pollen tubes is regulated by Rop1At, a Rop GTPase belonging to the Rho family. When overexpressed, Rop1At transformed SAB into a network of fine filaments and induced a transverse actin band behind the tip, leading to depolarized growth. These changes were due to ectopic Rop1At localization to the apical region of the plasma membrane and were suppressed by guanine dissociation inhibitor overexpression, which removed ectopically localized Rop1At. Rop GTPase–activating protein (RopGAP1) overexpression, or Latrunculin B treatments, also recovered normal actin organization and tip growth in Rop1At-overexpressing tubes. Moreover, overexpression of RopGAP1 alone disrupted SABs and inhibited growth. Finally, SAB oscillates and appears at the tip before growth. Together, these results indicate that the dynamics of tip actin are essential for tip growth and provide the first direct evidence to link Rho GTPase to actin organization in controlling cell polarity and polar growth in plants.

Key Words: Rho GTPase • cell polarity • polar growth • actin cytoskeleton • RopGAP

© 2001 The Rockefeller University Press

The online version of this article contains supplemental material.

Abbreviations used in this paper: CA, constitutively active; DN, dominant negative; GAP, GTPase-activating protein; GDI, guanine nucleotide dissociation inhibitor; GFP, green fluorescent protein; GM, germination medium; mTalin, mouse talin; PIP, phosphatidylinositol 4,5-bisphosphate; PM, plasma membrane; SAB, short actin bundle.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?

Related Article


J. Cell Biol. 2001 152: 0-2. [Full Text] [PDF]





  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents