Fig. 4. Peroxisomal location of Ant1p depends on the membrane protein targeting route. (A) Localization of an Ant1p–GFP fusion protein. The wild-type UTL-7A and the otherwise isogenic pex13Δ, pex19Δ and pex3Δ strains expressing Ant1p–GFP under oleic acid-induction conditions were examined for GFP fluorescence. Structural integrity of the cells is documented by bright-field microscopy. (B) Stability of the Ant1p–GFP fusion protein in pex mutants. The same strains as in (A) were induced for 14 h in rich oleate-containing medium. Whole-cell extracts of these samples were analyzed for the amount of Ant1p–GFP, mitochondrial Aac2p and cytosolic Pgk1p by immunological detection.