FIGURE 5.

Sec22 homodimers are associated with SNARE protein complexes. Washed semi-intact cells expressing Sec22HA in CBY773 and Sec22HA(D153C) in CBY773 were incubated in the absence (−) or presence (+) of 0.2 mm Cu²⁺/phen. Reactions were quenched with NEM and membranes were solubilized in Triton X-100 for immunoprecipitation of the target proteins Sed5, Sly1, or Gos1. Total solubilized extracts (T) and immunoprecipitates (IP) were resolved by non-reducing SDS-PAGE and immunoblotted for the indicated proteins. A, protein recovered in Sed5 immunoprecipitations. B, proteins recovered in Sly1 immunoprecipitations. C, proteins recovered in Gos1 immunoprecipitations. Total lanes represent 1/20 of the solubilized extracts loaded in the IP lanes. Erv41 serves as a specificity control and was not efficiently recovered in immunoprecipitation reactions. Note the Sec22HA dimer (22HA × 22HA) was recovered after cross-linking the D153C variant in Sed5, Sly1, and Gos1 immunoprecipitations.