Exploring Arylidene-Indolinone Ligands of Autophagy Proteins LC3B and GABARAP.

We report the first structure-activity studies of arylidene-indolinone compound which was reported as a ligand of autophagy-related protein LC3B. The literature has conflicting information on the binding affinity of this compound and there is some debate regarding its use as a component of autophagy-dependent degrader compounds. We developed an AlphaScreen assay to measure competitive inhibition of the binding of known peptide ligands to LC3B and its paralog GABARAP.