Recombinant Human K11-linked Di-Ubiquitin

Background: K11-linked ubiquitin chains are formed when the C-terminal glycine of one ubiquitin is conjugated to lysine 11 of another, producing homotypic or mixed polyubiquitin chains. They are assembled primarily by the E2 enzyme UBE2S in conjunction with APC/C. K11 linkages target substrates for proteasomal degradation, especially during cell cycle progression, controlling levels of cyclins and mitotic regulators. They also regulate endoplasmic reticulum-associated degradation (ERAD) and signaling pathways by modulating substrate fate and interactions with ubiquitin receptors that distinguish linkage types. Deubiquitylases such as Cezanne (OTUD7B) disassemble K11 chains, fine-tuning cellular proteostasis.