Immunofluorescence was performed as described [47 (link)] using antibodies against Podocalyxin (catalog # PA1-46169; Thermo Fisher Scientific) and Syntaxin-4 (catalog # 610439; BD Biosciences; San Jose, CA). Confocal analyses were performed using an Olympus FV3000 confocal microscopy system (Olympus; Waltham, MA).