Within the intricate molecular landscape inside of a cell, the orchestration of proteins demands precise control to avoid disease. While some proteins must be synthesized at specific times, others require timely breakdown and recycling. Protein degradation is a fundamental process that influences cellular activities such as the cell cycle, cell death, or immune response.
At the core of this process lies the proteasome, a recycling hub in the cell. The proteasome degrades proteins if they carry a molecular tag formed by a chain of ubiquitin molecules. The task of attaching this tag falls to enzymes known asThis process, known as polyubiquitination, has long been difficult to study due to its rapid and complex nature.
To tackle this challenge, scientists at the IMP Research Institute of Molecular Biology in Vienna, the University of North Carolina School of Medicine, and collaborators employed a combination of techniques, integratingDavid Haselbach, Ph.D., a group leader at the IMP, said,"Our aim was to capture polyubiquitination step by step through time-resolved cryo-EM studies.