Colocalization of presenilin and SERCA2b. (A) Confocal images of fibroblasts showing dual staining for PS1 or PS2 (red) together with SERCA2b (green). Merged images with sites of colocalization in yellow are shown on the right. (B) Western blots show coimmunoprecipitation of SERCA2b with PS1 and PS2 in fibroblast cell lysates. Polyclonal rabbit anti-PS1 or -PS2 antibodies were used to immunoprecipitate SERCA2b, which was then detected using anti-SERCA2b antibody. No SERCA2b immunoprecipitation was apparent with a control (rabbit polyclonal anti-p35) antibody. Bar, 10 μm.