Fig. 4. Ultrastructure of opsin aggresomes. Electron micrograph of a COS-7 cell with a P23H-GFP mutant aggresome. (i) The aggresome (A) forms near the nucleus (N) and centrosome (C) and is surrounded by mitochondria (M). (ii) At higher magnification the intermediate filaments (IF) that surround the aggresome can be seen. (iii) The aggresome also has a high membrane content and in places appears to be surrounded by membrane (arrowheads). Bar, 1 µm.