Plant Villin, Lily P-135-ABP, Possesses G-Actin Binding Activity and Accelerates the Polymerization and Depolymerization of Actin in a Ca2+-Sensitive Manner

• DOI: 10.1093/pcp/pci185
• Publication Date: 2005-08-14T00:12:55Z
• Authors: Etsuo Yokota; Motoki Tominaga; Issei Mabuchi; Yasunori Tsuji; Christopher J. St...; Kazuhiro Oiwa; Teruo Shimmen
• Keywords: Depolymerization; MDia1; Treadmilling; Profilin; Actin-binding protein; Actin remodeling

From germinating pollen of lily, two types villins, P-115-ABP and P-135-ABP, have been identified biochemically. Ca(2+)-CaM-dependent actin-filament binding bundling activities demonstrated for both villins previously. Here, we examined the effects lily on polymerization depolymerization actin. P-135-ABP present in a crude protein extract prepared from bound to DNase I affinity column Ca(2+)-dependent manner. Purified reduced lag period that precedes actin filament monomers presence either Ca(2+) or Ca(2+)-CaM. These results indicated can form complex with G-actin this acts as nucleus filaments. However, nucleation activity is probably not relevant vivo because assembly saturated profilin, situation mimics conditions found pollen, was accelerated P-135-ABP. also enhanced filaments during dilution-mediated disassembly. Growth barbed ends Ca(2+)-CaM prevented, consistent capping activity. suggested villin involved only arrangement into bundles basal shank region tube, but regulating modulating dynamics through its (or fragmentation) apical where there relatively high concentration Ca(2+).