Unable to connect to database - 19:01:15 Unable to connect to database - 19:01:15 SQL Statement is null or not a SELECT - 19:01:15 SQL Statement is null or not a DELETE - 19:01:15 Botany & Plant Biology 2007 - Abstract Search
Unable to connect to database - 19:01:15 Unable to connect to database - 19:01:15 SQL Statement is null or not a SELECT - 19:01:15

Abstract Detail


Cytoskeleton Structure and Dynamics

Thomas, Clément [1], Moreau, Flora [2], Hoffmann, Céline [2], Gatti, Sabrina [2], Hofmann, Christina [3], Van Troys, Marleen [4], Ampe, Christophe [4], Steinmetz, André [2].

The tobacco WLIM1 protein triggers the formation of actin bundles through its LIM domains.

Actin filament stabilization and bundling, i.e. the formation of actin cables, is a very important process that relies on proteins able to bind directly and crosslink several subunits of actin filaments. The tobacco WLIM1 gene encodes a two LIM domain-containing protein that was recently shown to define a new family of actin cytoskeleton regulators in plants. We conducted a domain analysis that identified the LIM domains as the peptidic motifs responsible for the F-actin binding and bundling activities of WLIM1. High-speed cosedimentation assays revealed that the deletion of one of the two LIM domains reduces significantly but did not abolish the ability of WLIM1 to bind actin filaments. Individual recombinant LIM domains were found able to interact directly with actin filaments, although with a reduced affinity compared to the full-length protein, indicating that they function as autonomous F-actin binding elements in vitro. The ability of different deletion variant proteins and individual LIM domains to stabilize and bundle actin filaments was investigated using a pyrene-labelled actin depolymerization assay as well as by low-speed cosedimentation. Variants lacking the C-terminal domain or harbouring a reduced inter-LIM spacer displayed very similar F-actin stabilizing and bundling activities as the full-length WLIM1 protein. In contrast, the deletion of one of the two LIM domains negatively impacted both activities, indicating that WLIM1 triggers the formation of actin bundles through its LIM domains. The structure of the actin bundles formed in presence of the different WLIM1 variants was analyzed by electron microscopy. A model for actin bundle formation is proposed.


Log in to add this item to your schedule

1 - Centre de Recherche Public-Santé, Plant Molecular Biology, 84, Val Fleuri, Luxembourg, L-1526, Luxembourg
2 - Centre de Recherche Public-Santé, Plant Molecular Biology
3 - Institut de Biologie Moleculaire des Plantes, Biologie moleculaire et cellulaire des interactions entre virus, plantes et vecteurs
4 - Faculty of Medecine and Health Sicences, Ghent University and Medical, Department of biochemistry
5 - Faculty of Medecine and Health Sicences, Ghent University and Medical, Department of biochemistry

Keywords:
actin
cytoskeleton
LIM domain
actin bundles.

Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P23001
Abstract ID:113


Copyright © 2000-2007, Botanical Society of America. All rights