Interaction Between a Gelsolin from Dendrorhynchus zhejiangensis with Three Gelsolin-Like Domains and Actin In Vitro.

The gelsolin family proteins are best known for involvement in cytoskeletal rearrangement by controlling actin organization during a variety of cellular processes. Previously, a 1962 bp cDNA encoding a 41.7 kDa protein with three gelsolin-like domains (G domains) from Dendrorhynchus zhejiangensis was identified and named as DzGSN. In this study, the sequence and function of a novel member of the gelsolin family proteins from D. zhejiangensis have been analyzed. Sequence alignment indicates that DzGSN is highly homologous to human gelsolin (35% identity) and human CapG (36% identity). The important functional motifs and critical amino acids were identified. The nucleating- and severing-actin activities of recombinant DzGSN (rDzGSN) were then investigated by using atomic force microscopy in vitro. After incubation with rDzGSN in the presence of Ca2+, global actin (G-actin) was observed to aggregate into a ring structure, while filament actin (F-actin) was observed to be shortened. Additionally, the yeast two-hybrid system also verified that DzGSN can interact with actin. The results provide new insight into functional diversity and evolution of gelsolin family proteins.