Ca2+-dependent actin filament-severing protein that has a regulatory function in exocytosis by affecting the organization of the microfilament network underneath the plasma membrane (PubMed:8547642, PubMed:26365202). Severing activity is inhibited by phosphatidylinositol 4,5-bis-phosphate (PIP2) . In vitro, also has barbed end capping and nucleating activities in the presence of Ca2+. Required for megakaryocyte differentiation, maturation, polyploidization and apoptosis with the release of platelet-like particles (PubMed:11568009). Plays a role in osteoclastogenesis (OCG) and actin cytoskeletal organization in osteoclasts . Regulates chondrocyte proliferation and differentiation . Inhibits cell proliferation and tumorigenesis. Signaling is mediated by MAPK, p38 and JNK pathways (PubMed:11568009).