Detection of apoptotic proteins by immunofluorescence in human retinal pigment epithelium cells after exposure to 20 μM xanthurenic acid for one week (magnification 200-fold). Panels a-c from left to right represent immunodetection of apoptotic protein with respective antibody, staining of nucleus with Hoechst, and merge of both. No staining for these enzymes was observed in control cells. a, Detection of active caspase-3 pl7. b, Detection of PARP p85. c, Detection of active caspase-9. Panel d, Detection of N-half of gelsolin bound to the cytoskeleton. From left to right: without xanthurenic acid, with 10 μM xanthurenic acid, with 20 μM xanthurenic acid. e, Detection of cleaved gelsolin containing polyphosphoinositide binding domain by antibody directed against GPIP1 in apoptotic cells. From left to right: first two panels, control cells; Hoechst staining, no staining with antibody directed against GPIP1. Next two panels: cells incubated for one week with 20 μM xanthurenic acid; Hoechst staining, staining with antibody against GPIP1.