Plant actin cytoskeleton: New functions from old scaffold

Abstract

The actin cytoskeleton plays an essential role in several biological processes in plants, including cell division, cell expansion, organelle movement, vesicle trafficking, and the establishment of polar cell growth. To function properly, actin has to undergo continuous rounds of dynamic remodeling as the plant is presented with a constant stream of endogenous and exogenous signals. Remodeling of the actin cytoskeleton in plants is modulated by a multitude of highly conserved actin-binding proteins (ABPs). In recent years, additional proteins that interact directly or indirectly with actin have been uncovered. Although the precise roles of these newly described proteins have yet to be fully understood, initial studies suggest that they could confer actin functionalities and remodeling mechanisms that are distinct from those found in other eukaryotes. In this chapter, we briefly highlight some of the recent advances toward understanding how the actin cytoskeleton modulates plant growth, form, and adaptation to the environment. We focus primarily on live cell actin tools and on new insights about plant actin and ABP function culminating from the use of such tools. We also discuss some recently discovered plant proteins that function in actin-mediated biological processes that are unique to plants.