Binds to actin and affects the structure of the cytoskeleton. Slightly reduces actin polymerization. Binds to poly-L-proline, phosphatidylinositol 3-phosphate (PtdIns(3)P), phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), and phosphatidylinositol 4-phosphate (PtdIns(4)P). May be involved in spermatogenesis. Interacts with ACTRT3. Localizes first in the acroplaxome and later in the manchette during spermatid head development. Detected in round spermatids. Expression coincides with the increasing numbers of round spermatids and decreases during the termination of the first spermatogenic cycle. Belongs to the profilin family.