Gelsolin (GS)

Gelsolin is an actin-regulatory protein that modulates actin assembly and disassembly, and is believed to regulate cell motility in vivo through modulation of the actin network. In addition to its actin-regulatory function, gelsolin has also been proposed to affect cell growth.It is first isolated from rabbit lung macrophages as a modulator of the cytoplasmic actin gel−sol transformation. Gelsolin can sever actin filaments and cap the fast-growing ends of the filaments in vitro; this promotes actin disassembly. Gelsolin also has the ability to nucleate actin polymerization. These functions are activated by Ca2 and inhibited by polyphosphoinositides (PPIs). Such observations have led to the view that gelsolin regulates actin reorganization in response to changes in the concentrations of Ca2 and PPIs in living cells.