Ubiquitination and Protein Stability - Part B, Volume 619, the latest release in the Methods in Enzymology series, highlights new advances in the field, with this updated volume presenting interesting chapters written by an international board of authors. Topics of note include chapters on Assays of SUMO protease function in mammalian cells, In vitro analysis of proteasome-associated USP14 activity for substrate degradation and deubiquitylation, Methods to study proteasome regulatory particle assembly, Native mass spectrometry approaches to study the proteasome, Single-molecule methods to study the ubiquitin-proteasome system, Assays for the function of ubiquitin in the mammalian endocytic pathway, and much more.