Caveolin-1 (Cav-1) is required for aPC-dependent apoptosis inhibition in human podocytes. (A-B) Representative immunoblot images showing dissociation of PAR-2 and PAR-3 from Cav-1 and reorganization of Cav-1, PAR-2, and PAR-3 after treatment with aPC (20nM) in the presence or absence of MβCD (10mM). (C) Bar graph summarizing the frequency of apoptosis in PAN-treated Cav-1 knockdown human podocytes (Cav-1^KD, left) and representative image showing shRNA-mediated knockdown of Cav-1 in human podocytes (semiquantitative RT-PCR, right). aPC and activating peptides (AP) for PAR-2 or PAR-3 fail to prevent PAN-induced apoptosis in Cav-1–deficient podocytes. (D) Representative immunoblots showing levels of Phospho-Cav-1 (pCav-1 [Tyr-14]) after treatment with aPC (20nM) at different time points in control (wild-type, wt) and PAR-3KD podocytes (top panel) and bar graphs summarizing the results (bottom panel). APC induces dephosphorylation of Cav-1 only in the presence of PAR-3. (E) Bar graph summarizing the frequency of apoptosis in PAN-stressed Cav-1^KD human podocytes infected with adenoviral expression constructs, wild-type (Ad-Cav-1^wt), or a Cav-1 mutant (Ad-Cav-1^Y14A) and treated with aPC. aPC fails to protect against PAN-induced apoptosis in podocytes infected with phosphorylation-deficient Cav-1 mutant (Ad-Cav-1^Y14A). (F) Representative immunoblots showing expression of Cav-1 in Cav-1^KD podocytes transfected with adenoviral expression constructs (Ad-Cav-1^wt, Ad-Cav-1^Y14A). Data are mean ± SEM of at least 3 independent experiments. ^XP < .05 vs control. *P < .01 vs control (ANOVA).