Fig. 1.

Golgi structure disruption by GRASP KO increases GAG synthesis but reduces its secretion. A Schematic diagram illustrating the HS and CS synthesis pathways; major enzymes in each pathway are indicated at their designated steps of reactions. B Schematic workflow for cell lysate and medium sample preparation to analyze GAGs by LC–MS. C GRASP KO increases the amount of GAGs in cells. Shown are the amounts of GAGs in the lysates of wildtype (WT), GRASP55 knockout (55KO), GRASP65 knockout (65KO), and GRASP55 and GRASP65 double knockout (DKO) HeLa cells. D GRASP KO decreases GAG secretion. WT and indicated GRASP KO cells were incubated in serum-free medium for 8 h and GAGs in the conditioned media were analyzed by LC–MS. E GRASP KO increases the total amount of GAGs in cells and media. Shown is the total amount of GAGs per million cells in both cell lysates and conditioned medium in each cell line. Results are presented as mean ± SEM, statistical analysis was assessed by comparing KO cells to WT cells by Student’s t test. *p < 0.05; **p < 0.01; ***p < 0.001