Getting Close: Insight into the Structure and Function of K11/K48-Branched Ubiquitin Chains

K11/K48-branched ubiquitin chains are proteasomal priority signals that elicit the rapid elimination of mitotic regulators and aggregation-prone proteins. Indicative of an intriguing signaling mode, Boughton et al. (2019) unravel an interaction between distal subunits of K11/K48-branched ubiquitin trimers that could provide a combined surface for recognition by the proteasomal receptor RPN1.