Heterotypic Ubiquitin Chains: Seeing is Believing

The biological diversity of ubiquitination resides in the multivalent nature of linkage-specific homotypic and heterotypic ubiquitin (Ub) chains. A recent publication by Yau et al. in Cell describes the development of K11/K48-bispecific antibodies and a physiological role for K11/K48 heterotypic chains in regulation of the cell cycle and clearance of aggregated proteins.