Assessing Different E3 Ligases for Small Molecule Induced Protein Ubiquitination and Degradation.

Proteolysis targeting chimera (PROTAC) technology, the recruitment of E3 ubiquitin ligases to induce the degradation of a protein target, is rapidly impacting chemical biology, as well as modern drug development. Here, we explore the universality of this approach by evaluating different E3 ubiquitin ligases, engineered in their substrate binding domains to accept a recruiting ligand. Five out of six E3 ligases were found to be amenable to recruitment for target degradation. Taking advantage of the tight spatiotemporal control of inducing ubiquitination on a preselected target in living cells, we focused on two of the engineered E3 ligases, βTRCP and parkin, to unravel their ubiquitination characteristics in comparison with the PROTAC-recruited endogenous E3 ligases VHL and cereblon.