Actin Dynamics in the Plant Cell

Dynamic rearrangements of the actin cytoskeleton are one of the fastest responses of the plant cell to environmental signals and an important part of developmental programs. The turnover rate of actin microfilaments and supramolecular structures is several orders higher than that of actin proteins and mRNAs. The high rate of actin polymerization in the cell is provided by specific nucleating machineries, primarily by the Arp2/3 complex and formins. A wide set of actin-binding proteins capping, severing, cross-linking, and bundling actin filaments are involved in actin polymerization and depolymerization, accelerating these processes or protecting microfilaments against breakdown. The actin cytoskeleton is not only a target for various signals but also an effector for diverse physiological processes. Recently, some novel players in signaling to the plant actin cytoskeleton have been revealed, the WAVE complex and RIC proteins among them. The deciphering of signaling pathways from the actin cytoskeleton is only at the start. In this review, not all the relevant literature but mainly new developments in the field is summarized.