Thrombin-stimulated cell division involves proteolysis of its cell surface receptor.

A cell-surface component of molecular weight 43,000 is cleaved by thrombin on cells that divide after thrombin treatment, but is not cleaved on cells that are unresponsive to its mitogenic action. Studies with a photoreactive derivative of thrombin showed that its cell surface receptor has a molecular weight of 43,000. This indicates that thrombin must cleave its receptor to stimulate cell division.