(A) WB showing GRP78 levels in lysates from WT, GS28 KO, GS15 KO and COG4 KO cells treated with SubAB toxin for indicated time periods. (B) Quantification from GRP78 levels (n=3). After 180 mins of treatment with SubAB, 100% GRP78 is cleaved in WT and GS15 KO cells. However, in this time, only 50% is cleaved in GS28 KO and COG4 KO cells. (C) Airyscan images of the cis and trans Golgi compartments GM130 and TGN46 in SNARE-depleted cells show that TGN46 staining intensity in GS28 KO cells is reduced. (D) Compared to WT, there is a significant decrease in the colocalization (Pearson’s colocalization coefficient) between GM130 and TGN46 in GS28 KO cells **p<0.005, n≥30