Figure 4.

Catalase import in peroxisomes of patient fibroblasts harboring the G843D allele and different second mutated PEX1 alleles. Fibroblasts were cultured for 3 d at either 30°C or 37°C and then treated for indirect immunofluorescence. Catalase staining was diffuse, indicating a cytoplasmic localization at 37°C. At 30°C, catalase was imported into peroxisomes in most of the cells from patient 10 (as indicated by the punctuate staining pattern) but in only ∼10% of the cells of patient 1. The punctuate structures colocalized with the staining for the peroxisomal membrane protein PMP70 (data not shown).