Figure 8.

PαF aggregation is enhanced in kar2-1–derived mutant microsomes but can be resolubilized by wild-type BiP. ΔGppαF was translocated into microsomes derived from wild-type (•), kar2-1 (○), and kar2-133 (▴) cells, and kar2-1 yeast transformed with a KAR2 overexpression plasmid (pMR109; □). The microsomes were washed and incubated at 37°C for 30 min before Triton X-100 extraction and sedimentation in a 5–40% sucrose gradient. The percentages of pαF, the in vitro ERAD substrate, in fractions from the top (fraction 1) to the bottom (fraction 14) of the gradient are shown.