Figure 2.

Mutant decorin is retained in the cytoplasm. A: HEK293T cells were seeded on collagen I–coated coverslips before transfection and immunolocalization assays. Most WT decorin was secreted and associated with collagen I. B: In contrast, compared with WT decorin, mutant decorin was not detectable outside the cell, and much higher immunoreactivity was observed in the cytoplasm (arrows). C: Distribution in medium and cell layer was different between WT and mutant decorin. Using cotransfected green fluorescent protein as a loading control, immunoblots showed that almost 90% of WT decorin was secreted into the medium. In contrast to the WT form, mutant decorin was undetectable in the medium, although levels of cell layer–associated decorin were similar between the two forms of decorin. These data clearly demonstrate that mutant decorin was retained in the cytoplasm.