Abstract
We have isolated two types of plant villin, P-135-ABP and P-115-ABP. Although the gelsolin/severin domain, in which Ca-sensitive G-actin binding and depolymerizing activities reside, is well conserved between animal and lily villin, these activities of lily villin have not been shown yet. In the present study, we explored these activities of lily villin by DNase I affinity column chromatography, precipitation assay using ultra-centrifugation, fluorimetric assay using pyrene-labeled actin and the visualization of F-actin stained with fluorescence-labeled phalloidin. Both lily villins were associated with DNase I column in a Ca-sensitive manner. Furthermore, P-135-ABP accelerated the polymerization and depolymerization of actin in the presence of Ca, especially Ca-calmodulin. These results suggested that lily villin is involved in not only the arrangement of actin filaments into bundles but also in regulating and modulating actin dynamics through its G-actin binding and depolymerizing activities in pollen tubes.
