D. Summary of immunoblot analyses of ER-resident proteins level in cells that do not overexpress GFP-Snc1-PEM: WT (PEP4PRB1) vs pep4∆ prb1∆ (left), ypt1-1PEP4PRB1 vs ypt1-1pep4∆ prb1∆ (right). Immunoblots and quantification are shown in Fig 6B-6C and S6A-S6C Fig. In YPT1 cells, the levels of Sec61 and Hmg1 (green) are slightly increased (14 and 38%, respectively) in strains defective in vacuolar proteolysis; the levels of Sec12, Sec13 and Kar2 are not increased (blue and grey). The levels of Sec61 and Hmg1 (green) are increased by 2-2.5 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). 