Vps52p, Vps53p, and Vps54p are major components of the immunopurified Vps52/53/54 complex. Radiolabeled strains expressing integrated, HA-tagged forms of Vps52p (LCY226; lanes 2 and 6), Vps53p (LCY229; lanes 3 and 7), Vps54p (LCY233; lanes 4 and 8), and the untagged parent strain (SNY36-9B; lanes 1 and 5) were spheroplasted and lysed under denaturing (lanes 1–4) or nondenaturing (lanes 5–8) conditions, and the extracts were subjected to immunoprecipitation with anti-HA antiserum. Four times as many cells were used for the native immunoprecipitation (see MATERIALS AND METHODS). The positions of wild-type and tagged forms of Vps52p, Vps53p, and Vps54p are indicated on the right. The presence of the triple-HA epitope tag is predicted to add an additional 5 kDa to the molecular mass of each protein.