<prompt> Thrombosthenin is aCoagulation factorContractile proteinA thrombosis promoting proteinA protein regulating platelet production  <response>: Thrombasthenin, 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. 