The LIM domains of WLIM1 define a new class of actin bundling modules

Clément Thomas*, Flora Moreau, Monika Dieterle, Céline Hoffmann, Sabrina Gatti, Christina Hofmann, Marleen Van Troys, Christophe Ampe, André Steinmetz

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

35 Citations (Scopus)

Abstract

Actin filament bundling, i.e. the formation of actin cables, is an important process that relies on proteins able to directly bind and cross-link subunits of adjacent actin filaments. Animal cysteine-rich proteins and their plant counterparts are two LIM domain-containing proteins that were recently suggested to define a new family of actin cytoskeleton regulators involved in actin filament bundling. We here identified the LIM domains as responsible for F-actin binding and bundling activities of the tobacco WLIM1. The deletion of one of the two LIM domains reduced significantly, but did not entirely abolish, the ability of WLIM1 to bind actin filaments. Individual LIM domains were found to interact directly with actin filaments, although with a reduced affinity compared with the native protein. Variants lacking the C-terminal or the inter-LIM domain were only weakly affected in their F-actin stabilizing and bundling activities and trigger the formation of thick cables containing tightly packed actin filaments as does the native protein. In contrast, the deletion of one of the two LIM domains negatively impacted both activities and resulted in the formation of thinner and wavier cables. In conclusion, we demonstrate that the LIM domains of WLIM1 are new autonomous actin binding and bundling modules that cooperate to confer WLIM1 high actin binding and bundling activities.

Original languageEnglish
Pages (from-to)33599-33608
Number of pages10
JournalJournal of Biological Chemistry
Volume282
Issue number46
DOIs
Publication statusPublished - 16 Nov 2007

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