WSC forms detergent-resistant complexes in the yeast peroxisome and also inhibits peroxisome biogenesis. (A) Yeast were transformed with an RFP-PTS1–expressing plasmid to reveal peroxisomes and then transformed with an empty plasmid (−WSC) or a WSC–GFP–expressing plasmid (+WSC). Bar, 5 μm. (B) The effect of WSC on peroxisome numbers was quantified by counting punctate signal from RFP-PTS1 in the indicated strains. 64 cells were counted for each strain. (C) WSC–GFP forms detergent-insoluble complexes in yeast. Examination of peroxisomes by fluorescence microscopy in the absence (buffer) and presence (1% TX-100) of detergent was conducted as described in Fig. 6 D. Bar, 1 μm. Panels presented in this figure were enlarged using the scaling function in Photoshop software. (D) Fractionation by density gradient centrifugation of extracts prepared from WSC–GFP–expressing yeast was done as described in Fig. 6 E in the absence (top) and presence (TX-100) of detergent. The bottom (B) and top (T) of the gradient are indicated.