Plant Physiol. Illumina
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on March 27, 2009; 10.1104/pp.109.135335

OPEN ACCESS ARTICLE
This Article
Free via Open Access: OA
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow Supplemental Data
Right arrowOA All Versions of this Article:
150/1/144    most recent
pp.109.135335v1
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 Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Takemiya, A.
Right arrow Articles by Shimazaki, K.-i.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Takemiya, A.
Right arrow Articles by Shimazaki, K.-i.
Agricola
Right arrow Articles by Takemiya, A.
Right arrow Articles by Shimazaki, K.-i.

Received January 6, 2009
Accepted March 24, 2009

Identification and Functional Characterization of Inhibitor-3, a Regulatory Subunit of Protein Phosphatase 1 in Plants

Atsushi Takemiya , Chie Ariyoshi , and Ken-ichiro Shimazaki *

Department of Biology, Faculty of Science, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan

* Corresponding author; email: kenrcb{at}mbox.nc.kyushu-u.ac.jp.

Protein phosphatase 1 (PP1) is a eukaryotic Ser/Thr protein phosphatase, and mediates diverse cellular processes in animal systems via the association of a catalytic subunit (PP1c) with multiple regulatory subunits that determine the catalytic activity, the subcellular localization, and the substrate specificity. However, no regulatory subunit of PP1 has been identified in plants so far. In this study, we identified inhibitor-3 (Inh3) as a regulatory subunit of PP1 and characterized a functional role of Inh3 in Vicia faba and Arabidopsis thaliana. We found Inh3 as one of the proteins interacting with PP1c using a yeast two-hybrid system. Biochemical analyses demonstrated that Arabidopsis thaliana Inh3 (At Inh3) bound to PP1c via the RVxF motif of At Inh3, a consensus PP1c-binding sequence both in vitro and in vivo. At Inh3 inhibited the PP1c phosphatase activity in the nanomolar range in vitro. At Inh3 was localized in both the nucleus and cytoplasm, and colocalized with Arabidopsis PP1c in these compartments. Disruption mutants of At INH3 delayed the progression of early embryogenesis, arrested embryo development at the globular stage, and eventually caused embryo lethality. Furthermore, reduction of At INH3 expression by RNA interference led to a decrease in fertility. Transformation of the lethal mutant of inh3 with wild-type At INH3 restored the phenotype, whereas that with the At INH3 gene having a mutation in the RVxF motif did not. These results define Inh3 as a regulatory subunit of PP1 in plants, and suggest that Inh3 plays a crucial role in early embryogenesis in Arabidopsis.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 2009 by the American Society of Plant Biologists