STAR Protocols (Dec 2023)
Preparation of site-specifically fluorophore-labeled polyubiquitin chains for FRET studies of Cdc48 substrate processing
Abstract
Summary: A critical step in the removal of polyubiquitinated proteins from macromolecular complexes and membranes for subsequent proteasomal degradation is the unfolding of an ubiquitin moiety by the cofactor Ufd1/Npl4 (UN) and its insertion into the Cdc48 ATPase for mechanical translocation. Here, we present a stepwise protocol for the assembly and purification of Lys48-linked ubiquitin chains that are fluorophore labeled at specific ubiquitin moieties and allow monitoring polyubiquitin engagement by the Cdc48-UN complex in a FRET-based assay.For complete details on the use and execution of this protocol, please refer to Williams et al. (2023).1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.