H. Summary of immunoblot analysis of ER-resident proteins level in cells overexpressing GFP-Snc1-PEM: WT (PEP4PRB1) vs pep4∆ prb1∆ (left), ypt1-1PEP4PRB1 vs ypt1-1pep4∆ prb1∆ (right). Immunoblots and quantification are shown in Fig 6F and 6G and S6F-S6H Fig. In YPT1 cells, like Snc1-PEM (black), the levels of Hmg1 and Sec61 (green) are increased >10 fold in strains defective in vacuolar proteolysis. In contrast, the levels of Sec12, Sec13 and Kar2 are not changed (blue and grey). Like Snc1-PEM (black), the protein levels of Hmg1 and Sec61 (green) are increased ~15 fold in ypt1-1 mutant cells when compared to WT cells, regardless if they are defective in vacuolar proteolysis or not. In contrast, the levels of Sec12, Sec13 and Kar2 are only slightly increased (blue and grey). +/- and error bars represent STDEV. Results in this figure represent at least two independent experiments. 