CAPZA1 (capping actin protein of muscle Z-line subunit alpha 1) is an actin-binding protein that regulates cytoskeletal dynamics and cellular behavior. CAPZA1 functions as part of the F-actin capping protein complex, binding to the barbed ends of actin filaments to control actin cytoskeleton remodeling 1. The protein plays a tumor suppressor role in multiple cancers, with overexpression associated with reduced cell migration, invasion, and epithelial-mesenchymal transition (EMT) 12. CAPZA1's regulatory mechanism involves interaction with phosphatidylinositol 4,5-bisphosphate (PIP2), which causes its release from F-actin and enables cytoskeletal remodeling under hypoxic conditions 3. Beyond cytoskeletal functions, CAPZA1 regulates autophagy by binding to LRP1 intracellular domain in the nucleus, preventing LAMP1 expression and inhibiting autolysosome formation, which affects Helicobacter pylori CagA degradation 4. In exosome biogenesis, CAPZA1 (along with CAPZB) is recruited by ALIX to prevent F-actin accumulation around multivesicular bodies, facilitating their trafficking for secretion 5. Clinically, CAPZA1 expression correlates with tumor prognosis across multiple cancer types, with higher expression generally associated with better outcomes and reduced metastasis 126.