Polyubiquitin has long been recognised as an intracellular signal. It now appears that different lysine linkages between the ubiquitin moieties are recognised as distinct signals and act in different cell processes. The generation of these different polyubiquitin chains may play an important part in the life of a cell.
Dubiel, W., & Gordon, C. (1999, August 12). Ubiquitin pathway: Another link in the polyubiquitin chain? Current Biology. Current Biology Ltd. https://doi.org/10.1016/S0960-9822(99)80353-4