(A) WB of Golgi SNAREs in WT, GS28 KO, GS15 KO and COG4 KO cells. (B) Quantification of fold changes in the total levels of tested SNAREs. GS15 is significantly depleted in GS28 KO cell lysates. In COG4 KO cell lysates, both GS28 and GS15 are significantly depleted. The amount of STX5 and YKT6 is unaffected by either SNARE or COG KO. (C) Airyscan images of STX5, GS28, GS15 and YKT6 in WT, GS28 KO and GS15 KO cell lines show all remaining STX5 partners are mostly Golgi localized in KO cells. The Golgi is stained with GM130. Scale bars are 5 μm. (D) The total intensity of Golgi localized GS15 is significantly reduced in GS28 KO cells but GS15 KO does not have any effect on GS28’s intensity at the Golgi. Quantification of GS15’s and GS28’s signal intensities in the Golgi region in GS28 KO and GS15 KO cells, respectively. n≥30, *p<0.05, **p<0.001, ***p<0.001