the assembly and fragmentation of actin are regulated by actin-modulating proteins such as profilin , which sequesters actin monomers , acumentin , which binds to the slow-growing end of actin fibers , and gelsolin , a calcium-regulated protein that binds to the fast-growing end of actin polymers and severs actin filaments .
C0001271
actin
C0025979
actin filaments