FIGURE 3.

The R282A mutation in ERp57 abolishes its interaction with calnexin and calreticulin. HT1080 cells expressing various V5-tagged ERp57 constructs (lanes 2–5) or untransfected (UT) cells (lane 1) were cross-linked with BMH and lysed, and the ectopically expressed V5-tagged ERp57 was immunoisolated with a V5-specific antibody. The resulting immunoisolated material was separated on a reducing SDS-PAGE gel, and calreticulin (Crt) (A) or calnexin (Cnx) (B) was identified following Western blotting (WB). WT, wild type; IP, immunoprecipitation.