Skip to main content

Main menu

  • Home
  • Content
    • Current Issue
    • Archive
    • Preview Papers
  • About
    • Editorial Board and Staff
    • About the Journal
    • Terms & Privacy
  • More
    • Alerts
    • Contact Us
  • Submit a Manuscript
    • Instructions for Authors
    • Submit a Manuscript
  • Other Publications
    • Plant Physiology
    • The Plant Cell
    • Plant Direct
    • The Arabidopsis Book
    • Teaching Tools in Plant Biology
    • ASPB
    • Plantae

User menu

  • My alerts
  • Log in

Search

  • Advanced search
Plant Cell
  • Other Publications
    • Plant Physiology
    • The Plant Cell
    • Plant Direct
    • The Arabidopsis Book
    • Teaching Tools in Plant Biology
    • ASPB
    • Plantae
  • My alerts
  • Log in
Plant Cell

Advanced Search

  • Home
  • Content
    • Current Issue
    • Archive
    • Preview Papers
  • About
    • Editorial Board and Staff
    • About the Journal
    • Terms & Privacy
  • More
    • Alerts
    • Contact Us
  • Submit a Manuscript
    • Instructions for Authors
    • Submit a Manuscript
  • Follow PlantCell on Twitter
  • Visit PlantCell on Facebook
  • Visit Plantae
In BriefIN BRIEF
Open Access

Battening Down the Hatches: A Role for CASEIN KINASE1-LIKE PROTEIN2 in Stomatal Closure

Kathleen L. Farquharson
Kathleen L. Farquharson
Science Editor
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Kathleen L. Farquharson

Published June 2016. DOI: https://doi.org/10.1105/tpc.16.00462

  • Article
  • Figures & Data
  • Info & Metrics
  • PDF
Loading
  • © 2016 American Society of Plant Biologists. All rights reserved.

Stomata are the tiny gateways that regulate gas exchange between the atmosphere and the internal tissues of the plant. Serving both as entry points for CO2 and as exit points for water vapor, stomata have important roles in photosynthesis and transpiration. Survival of the plant depends on its ability to open or close stomata rapidly in response to environmental and endogenous stimuli. For instance, excessive water vapor loss would result in dehydration, and it is thus critical that stomata close under dry conditions. Stomatal closure is mediated by a complex molecular cascade that culminates in the reduction of turgor pressure in the pair of guard cells surrounding the stomatal pore. The actin cytoskeleton of guard cells is remodeled during stomatal closure, changing from radial filaments in open guard cells to dense longitudinal bands in closed ones (Eun and Lee, 1997), and has long since been known to function in stomatal aperture regulation (Kim et al., 1995). However, the mechanism by which the actin cytoskeleton is remodeled during stomatal closure and the purpose of this remodeling are unclear.

Zhao et al. (2016) recently identified a mutant line harboring an insertion in the gene encoding CASEIN1-LIKE PROTEIN2 (CKL2) in a screen for mutants that wilt more readily than the wild type and are less sensitive to abscisic acid (ABA)-induced stomatal closure. The authors found that CKL2, which is expressed in many tissues of the plant, is induced by both ABA and water-loss treatment. To examine the subcellular localization of CKL2, the authors transformed both wild-type and ckl2 mutant plants with a CKL2pro:GFP-CKL2 construct. The construct rescued the stomatal closure defect and drought-sensitive phenotype of the mutant. The finding that GFP-labeled CKL2 formed filamentous networks in several cell types, including guard cells, suggested that CKL2 associates with cytoskeletal elements. Pharmacological studies showed that CKL2 colocalized with actin filaments, but not with microtubules. In addition, GFP-labeled CKL2 colocalized with rhodamine-phalloidin-stained actin filaments in a cell suspension. However, a cosedimentation assay showed that CKL2 does not bind to actin in vitro.

A comparison of fluorescently labeled actin microfilaments in wild-type and ckl2 guard cells showed that the actin filaments of the mutant were disrupted more rapidly by treatment with the actin-destabilizing drug latrunculin A than were those of the wild type, suggesting that CKL2 stabilizes actin filaments in guard cells. Further analysis showed that this actin-stabilizing activity of CKL2 is essential for the construction of longitudinal actin cables during ABA-induced stomatal closure. Finally, the authors showed that CKL2 interacts with and phosphorylates actin depolymerizing factor 4 (ADF4), thereby blocking its actin filament disassembly activity.

Based on these findings, the authors propose that CKL2 regulates actin cytoskeleton remodeling during stomatal closure by phosphorylating ADF4 (see figure). Future research should examine how actin filament remodeling affects cellular processes in guard cells to bring about changes in stomatal aperture.

Figure1
  • Download figure
  • Open in new tab
  • Download powerpoint

Simplified model of ABA-induced stomatal closure. Actin microfilaments undergo dramatic changes during stomatal closure, changing from radial filaments in open stomata (left), to a disorganized array in closing stomata (middle), to thick longitudinal cables in closed stomata (right). ABA-induced CKL2 blocks ADF activity late in this process, thereby stabilizing actin microfilaments. (Adapted from Zhao et al. [2016], Figure 8.)

Footnotes

  • www.plantcell.org/cgi/doi/10.1105/tpc.16.00462

  • ↵[OPEN] Articles can be viewed without a subscription.

References

  1. ↵
    1. Eun, S.O.,
    2. Lee, Y.
    (1997). Actin filaments of guard cells are reorganized in response to light and abscisic acid. Plant Physiol. 115: 1491–1498.
    OpenUrlAbstract
  2. ↵
    1. Kim, M.,
    2. Hepler, P.K.,
    3. Eun, S.O.,
    4. Ha, K.S.,
    5. Lee, Y.
    (1995). Actin filaments in mature guard cells are radially distributed and involved in stomatal movement. Plant Physiol. 109: 1077–1084.
    OpenUrlAbstract
  3. ↵
    1. Zhao, S.,
    2. Jiang, Y.,
    3. Zhao, Y.,
    4. Huang, S.,
    5. Yuan, M.,
    6. Zhao, Y.,
    7. Guo, Y.
    (2016). CASEIN KINASE1-LIKE PROTEIN2 regulates actin filament stability and stomatal closure via phosphorylation of actin depolymerizing factor. Plant Cell 28: 1422–1439.
    OpenUrlAbstract/FREE Full Text
PreviousNext
Back to top

Table of Contents

Print
Download PDF
Email Article

Thank you for your interest in spreading the word on Plant Cell.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Battening Down the Hatches: A Role for CASEIN KINASE1-LIKE PROTEIN2 in Stomatal Closure
(Your Name) has sent you a message from Plant Cell
(Your Name) thought you would like to see the Plant Cell web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Battening Down the Hatches: A Role for CASEIN KINASE1-LIKE PROTEIN2 in Stomatal Closure
Kathleen L. Farquharson
The Plant Cell Jun 2016, 28 (6) 1236; DOI: 10.1105/tpc.16.00462

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Request Permissions
Share
Battening Down the Hatches: A Role for CASEIN KINASE1-LIKE PROTEIN2 in Stomatal Closure
Kathleen L. Farquharson
The Plant Cell Jun 2016, 28 (6) 1236; DOI: 10.1105/tpc.16.00462
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
    • Footnotes
    • References
  • Figures & Data
  • Info & Metrics
  • PDF

In this issue

The Plant Cell: 28 (6)
The Plant Cell
Vol. 28, Issue 6
Jun 2016
  • Table of Contents
  • Table of Contents (PDF)
  • Cover (PDF)
  • About the Cover
  • Index by author
View this article with LENS

More in this TOC Section

  • Zones of Defense? SA Receptors Have It Under Control
  • The Lure of Lignin: Deciphering High-value Lignin Formation in Seed Coats
  • Got Rosettes? Phenotype Them Fast, Accurately, and Easily with ARADEEPOPSIS!
Show more IN BRIEF

Similar Articles

Our Content

  • Home
  • Current Issue
  • Plant Cell Preview
  • Archive
  • Teaching Tools in Plant Biology
  • Plant Physiology
  • Plant Direct
  • Plantae
  • ASPB

For Authors

  • Instructions
  • Submit a Manuscript
  • Editorial Board and Staff
  • Policies
  • Recognizing our Authors

For Reviewers

  • Instructions
  • Peer Review Reports
  • Journal Miles
  • Transfer of reviews to Plant Direct
  • Policies

Other Services

  • Permissions
  • Librarian resources
  • Advertise in our journals
  • Alerts
  • RSS Feeds
  • Contact Us

Copyright © 2021 by The American Society of Plant Biologists

Powered by HighWire