[Profilins in plant cells].

Actin cytoskeleton is one of the major components of cytoskeleton in eukaryotic cells. In response to endogenous cues or external signals, actin filaments undergo quick polymerization and depolymerization with result in rapid reconstruction of actin cytoskeleton. The dynamic rearrangement of actin filaments in cells are regulated by actin-binding proteins. Profilin is a low-molecular-weight, actin-monomer-binding protein ubiquitously presents in organisms ranging from amoebae and fungi up to higher plants and mammals. Besides binding actin, profilin also binds to phosphatidylinositol 4,5-bisphosphate and poly-L-proline. Recent studies suggest that profilin is a multifunctional protein that has positive and negative regulatory effects on actin polymerization and, in certain case, may be involved in signal transduction. We have long been engaged in the studies on characteristic and function of profilin in plant cells, such as the function analysis of Arabidopsis PRF1 and PRF2, and the effects of profilin on the function of forming in modulating actin cytoskeleton. Here, with the combination of our results, we have reviewed the recent progress in profilin research, including its initial finding, biochemical properties, in vivo distribution and functions, as well as its role in signal transduction.