A Pathway Sensor for Genome-Wide Screens of Intracellular Proteolytic Cleavage

Protein cleavage is a central event in many regulated biological processes. We describe a system for detecting intracellular proteolysis based on non-conventional secretion of Gaussia luciferase (GLUC). GLUC exits the cell without benefit of a secretory leader peptide, but can be anchored in the cell by fusion to \(\beta\)-actin. By including protease cleavage sites between GLUC and \(\beta\)-actin, proteolytic cleavage can be detected. Using this assay, we have identified regulators of autophagy, apoptosis and \(\beta\)-actin cleavage.