Skip Navigation



Plant and Cell Physiology Advance Access published online on October 23, 2007
Plant and Cell Physiology, doi:10.1093/pcp/pcm145
This Article
Right arrow Advance Access manuscript (PDF)
Right arrow All Versions of this Article:
48/12/1809    most recent
pcm145v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Miwa, K.
Right arrow Articles by Mizuno, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Miwa, K.
Right arrow Articles by Mizuno, T.
Agricola
Right arrow Articles by Miwa, K.
Right arrow Articles by Mizuno, T.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2007. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org

Identification of Amino Acid Substitutions that Render the Arabidopsis Cytokinin Receptor Histidine Kinase AHK4 Constitutively Active

Kumiko Miwa, Kuniko Ishikawa, Kazunori Terada, Hisami Yamada, Tomomi Suzuki, Takafumi Yamashino1 and Takeshi Mizuno

Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Furocho, Chikusa-ku, Nagoya 464-8601, Japan

Corresponding author: Takafumi Yamashino, Address: Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Furocho, Chikusa-ku, Nagoya, 464-8601, Japan., E-mail: yamasino{at}agr.nagoya-u.ac.jp, Tel: +81-52-789-4090, Fax: +81-52-789-4091


  Abstract

In Arabidopsis, three genes (AHK2, AHK3, and AHK4/CRE1) encode His-kinases, which serve as cytokinin receptors. To understand how the external cytokinin signal activates the His-kinase across the cell membrane, we exploited the power of microbial genetics to isolate several AHK4 mutants that function independently of cytokinin in both prokaryotic and eukaryotic assay systems. In each mutant, a single amino acid substitution within the second membrane-spanning segment, or within the region around the phosphorylation His site, renders the His-kinase constitutively active. These mutant receptors appear to have a "locked-on" conformation, even in the absence of stimulus. We discuss the implications of these data for the structure and function of the cytokinin receptor His-kinases in plants.

Keywords: cytokinin assay system with microbial cells - cytokinin receptor - His-Asp phosphorelay signaling - His-kinase - structure and function

(Received September 27, 2007; Accepted October 20, 2007)
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.