Fibrin is a cofactor for plasminogen activation by tissue plasminogen activator. The activation of initiator caspases requires binding to specific oligomeric activator protein. Alteplase is a manufactured form of tissue plasminogen activator. Enzyme target mechanisms include activator or inhibitor. Injection of tissue plasminogen activator (a fibrinolytic drug) in the CSF improved glymphatic functioning. I pro-collagens, and tissue plasminogen activator. Further thrombotic events could be treated with tissue plasminogen activator (tPA). These medications include tissue plasminogen activator, reteplase, streptokinase, and tenecteplase. This orphan receptor (endogenous ligand unknown) behaves as a constitutive activator of transcription. Prostaglandin E2 is an essential activator of the canonical Wnt signaling pathway. It may be either an activator or an inhibitor of the enzyme. PGE2 is a potent activator of the Wnt signaling pathway. The balance between repressor and activator E2F regulate cell cycle progression. Endothelial-ADPase degrades the platelet activator ADP. Wnt signaling is a strong activator of mitochondrial biogenesis.