F2R (PAR1) mediates multiple cytoprotective effects of Activated proein C (APC) (Riewald et al. 2002, Griffin et al. 2007). In most, but not all, reported studies of APC’s beneficial effects on endothelial cells, the cellular receptors EPCR and F2R are required. These cytoprotective effects include anti-apoptotic activities, anti-inflammatory activities, protection of endothelial barrier functions, and favorable alteration of gene expression profiles. This paradigm in which EPCR-bound APC activates F2R to initiate signaling is consistent with many in vitro and in vivo data. Localization of APC signaling to caveolin-1-rich microdomains (caveolae) may help differentiate mechanisms for cytoprotective APC signaling versus proinflammatory thrombin signaling. Additional mechanisms for APC effects on cells may involve other receptors. These effects include APC anti-inflammatory effects on leukocytes or cytoprotective effects on dendritic cells and neurons. Other receptors may include F2RL2 (PAR3), various integrins e.g., Mac-1 (CD11b/CD18), Beta-1 integrins, Beta-3 integrins, S1P1, or the apolipoprotein E receptor 2 (LRP8) (Mosnier et al. 2007).