Actin bundling in plants.
Tight regulation of plant actin cytoskeleton organization and dynamics is crucial for numerous cellular processes including cell division, expansion and intracellular trafficking. Among the various actin regulatory proteins, actin-bundling proteins trigger the formation of bundles composed of several parallel actin filaments closely packed together. Actin bundles are present in virtually all plant cells, but their biological roles have rarely been addressed directly. However, decades of research in the plant cytoskeleton field yielded a bulk of data from which an overall picture of the functions supplied by actin bundles in plant cells emerges. Although plants lack several equivalents of animal actin-bundling proteins, they do possess major bundler classes including fimbrins, villins and formins. The existence of additional players is not excluded as exemplified by the recent characterization of plant LIM proteins, which trigger the formation of actin bundles both in vitro and in vivo. This apparent functional redundancy likely reflects the need for plant cells to engineer different types of bundles that act at different sub-cellular locations and exhibit specific function-related properties. By surveying information regarding the properties of plant actin bundles and their associated bundling proteins, the present review aims at clarifying why and how plants make actin bundles.
Thomas
Clément
C
Plant Molecular Biology Laboratory, Centre de Recherche Public-Santé, L-1526 Luxembourg. clement.thomas@crp-sante.lu
Tholl
Stéphane
S
Moes
Danièle
D
Dieterle
Monika
M
Papuga
Jessica
J
Moreau
Flora
F
Steinmetz
André
A
D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D002455:Cell Division; D049108:Cell Enlargement; D003595:Cytoplasmic Streaming; D008840:Microfilament Proteins / Q000378:metabolism* / Q000648:ultrastructure; D010944:Plants / Q000378:metabolism* / Q000648:ultrastructure; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary
D000199:Actins; D008840:Microfilament Proteins