Figure 5

Interactions of Sec61p and Ssh1p bait proteins in the split ubiquitin system. Prey fusion proteins were expressed in heterozygous diploid SEC61/SEC61-CPLV (A) or heterozygous diploid SSH1/SSH1-CPLV yeast (B). Interactions were monitored by growth in the absence of histidine (-HLW) and ß-galactosidase activity leading to blue staining on Xgal plates (left) or measured in liquid ß-galactosidase assays (right). Expression of ALG5-Nub was used as negative control (- control), a haploid strain expressing WBP1-CPLV and OST1-Nub as positive control (+ control). Plates contaning histidine were used for growth control (-LW), and plates containing glycerol (YPG) to monitor growth on a non-fermentable carbon source for SSH1-CPLV strains. For liquid ß-galactosidase assays cells were grown to OD600 = 1.0, and activity measured as described in the Methods section. Values from six samples were averaged for each bait-prey combination.