Calcium-regulated, actin-modulating protein that binds to the plus (or barbed) ends of actin monomers or filaments, preventing monomer exchange (end-blocking or capping). It can promote the assembly of monomers into filaments (nucleation) as well as sever filaments already formed. May play a role in ciliogenesis (By similarity). A cytoplasmic form may also exists. Belongs to the villin/gelsolin family.