FLI-06 is a novel potent and selective small molecule intercepting Notch signaling and the early secretory pathway (EC50 ~2.3 μM), identified by using automated microscopy to monitor the trafficking and processing of a ligand-independent Notch-GFP fusion reporter.

FLI-06 can induce accumulation of the reporter at the plasma membrane by interfering with transport in the secretory pathway. It can also disrupt the Golgi apparatus in a manner distinct from that of brefeldin A and golgicide A. FLI-06 inhibited general secretion at a step before exit from the endoplasmic reticulum (ER), which was accompanied by a tubule-to-sheet morphological transition of the ER, rendering FLI-06 the first small molecule acting at such an early stage in secretory traffic. FLI-06 is a very useful chemical probe to study the inhibition of membrane traffic at pre- ER-exit site (ERES) stages without fusion of ER-Golgi.