Bioluminescence-based reporters for characterizing inhibitors and activators of human Sonic Hedgehog protein autoprocessing in live cells at high throughput

Abstract

The Sonic hedgehog (SHh) precursor protein undergoes biosynthetic autoprocessing to cleave off and cholesterylate the SHh signaling ligand, a vital morphogen and oncogenic effector protein. Autoprocessing is self-catalyzed by SHhC, the SHh precursor’s enzymatic domain. Here we describe the development and validation of the first cellular reporter to monitor human SHhC autoprocessing non-invasively in high-throughput compatible plates. The assay couples intracellular SHhC autoprocessing to the extracellular secretion of the bioluminescent nanoluciferase enzyme. We developed a wild-type (WT) SHhC reporter line for evaluating potential autoprocessing inhibitors by concentration response-dependent suppression of extracellular bioluminescence. A conditional mutant SHhC (D46A) reporter line was developed for identifying potential autoprocessing activators by a concentration response-dependent gain of extracellular bioluminescence.