Mechanism of microtubule rod formation in 13-lined ground squirrel (Ictidomys tridecemlineatus) platelets

Blood platelets play a critical role in blood clotting, or hemostasis. Platelets from human, baboon, and mouse are sensitive to cold, resulting in rapid removal from blood circulation by macrophages in the liver. Short shelf life at room temperature has led to a worldwide shortage of platelets. An understanding of how to prolong platelet shelf life is a high priority of platelet research. 13-lined ground squirrel (Ictidomys tridecemlineatus) platelets undergo significant morphological changes, forming rod shapes, when exposed to cold temperature. However, to date, little research has been done to uncover the correlation between the morphological changes and ground squirrel platelets' survival during hibernation. In this study, we confirmed that microtubules are responsible for ground squirrel platelet shape changes when exposed to different temperatures. Microtubules from ground squirrel platelets are maintained in equilibrium between rod and ring conformations. Microtubule polymerizations leads platelets to form rods. Microtubule depolymerization leads platelets to form rings. Low temperature acts as an inhibitor of microtubule depolymerization shifting platelet equilibrium to rod shapes