Binds to actin and affects the structure of the cytoskeleton. At high concentrations, profilin prevents the polymerization of actin, whereas it enhances it at low concentrations. By binding to PIP2, it inhibits the formation of IP3 and DG. Also binds to poly(L-proline) and phosphatidylinositol 4,5-bisphosphate micelles. Occurs in many kinds of cells as a complex with monomeric actin in a 1:1 ratio. In embryos, expression is specifically detected in body wall muscle cells. In adults, expression is localized to a striking dot-like fashion in body wall muscle. Belongs to the profilin family.