- The endothelial cell protein C receptor (EPCR) functions as a primary receptor for protein C activation on endothelial cells in arteries, veins, and capillaries. Ye, X., Fukudome, K., Tsuneyoshi, N., Satoh, T., Tokunaga, O., Sugawara, K., Mizokami, H., Kimoto, M. Biochem. Biophys. Res. Commun. (1999)