NGI-1 derivative C-19 is a specific, small-molecule inhibitor of oligosaccharyltransferase (OST) catalytic subunit STT3B, without effect on STT3A.
NGI-1 derivative C-19 reduces ligand stimulated activation of EGFR, in STT3A-ko cells, where EGFR glycosylation is dependent on STT3B alone, does not reduce glycosylation and ligand stimulation of EGFR in parental and STT3B-ko cells.
NGI-1 derivative C-19 has discrete biological effects on endogenous STT3B target proteins such as COX2 but does not activate the cellular unfolded protein response (UPR).
