Prof. Dr. Dieter H. Wolf together with Prof. Dr. Thomas Sommer, Max-Delbrück Center for Molecular Medicine, Berlin, have served as editors of a new review issue of Biochimica Biophysica Acta Molecular Cell Research on the Ubiquitin-Proteasome System. The issue, with its 19 articles from experts in the field, covers the newest developments on the structure and regulation of the proteasome, the function of ubiquitin and ubiquitin family proteins, the regulation of cellular functions by the system as well as connected diseases. Together with Ingo Amm the editors served as authors of the article on "Protein quality control and elimination of protein waste: The role of the ubiquitin-proteasome system".