Figure 10. The proposed model for thrombin regulation of the Cyr61 protein in cultured human corneal stromal fibroblasts and myofibroblasts. Thrombin regulates the Cyr61 protein through two mechanisms: 1) Thrombin stimulates stromal fibroblast and myofibroblast Cyr61 synthesis in part through PAR-1, at least for fibroblasts; 2) Thrombin induces, activates, or sequentially induces and activates at least one extracellular leupeptin-sensitive protease capable of cleaving Cyr61.