Fig. 2: Golgi complex is the main site where MT-KIT initiates downstream oncogenic signaling.

A The status of downstream effector molecules in the KIT signaling pathway was analyzed by western blotting GIST cells with or without treatment with Brefeldin A (BFA, 5āµg/mL) for 4āh, a compound that blocks ER to Golgi trafficking. B The same analysis was performed as in A using GIST cells with or without treatment for 18āh with 1 or 10āµM 30N12, a compound that blocks trans-Golgi trafficking to the plasma membrane (PM). C Immunoprecipitation of GIST430 and GIST882 cell lysates was performed to evaluate the interaction of MT-KIT with P85 and GRB2, the most upstream molecules of the PI3K/AKT pathway and MAPK/ERK pathway, respectively. D, E Confocal microscopic analysis of KIT, GRB2, P85, and GM130 in GIST cells transfected with HA-GRB2 or HA-P85 expression vectors was performed. HA-GRB2 and HA-P85 were labeled with hemagglutinin (HA).