<prompt> Thrombosthenin is:Coagulation factorContractile proteinA thrombosis promoting proteinA protein regulating platelet production  <response>: Thrombosthenin, platelet contractile proteins contract and help in clot retraction 48 hours after injury. the contractile protein of platelets is, responsible for clot retraction , platelet aggregation, and release of ADP and other biologic amines essential to platelet function. 