“泛素调控着真核细胞内的多种生命活动，不同泛素通过不同方式连接成具有复杂拓扑结构的多聚泛素链决定了蛋白的不同命运，包括导向蛋白酶体降解、蛋白质运输、DNA损伤修复、免疫信号转导等。不同的泛素可以被某些泛素相关域（ubiquitin-asso

"Ubiquitin regulates various cellular processes in eukaryotic cells, and different ubiquitins connected in different ways form complex topological structures of polyubiquitin chains that determine the fate of proteins, including targeting to proteasomal degradation, protein transport, DNA damage repair, immune signaling, etc. Different ubiquitins can be recognized by certain ubiquitin-associated domains (UBAs). UBA domains have been identified in 10 members of the mammalian AMPK-related kinase family (MARK1, MARK2, MARK3, MARK4, SIK, QIK, QSK, BRSK1, BRSK2, SNRK) located immediately after their kinase domains. In this study, we found that the UBA domains of hSNRK and hMARK3 in this protein kinase family can bind to ubiquitin both in vitro and in cell lysates, and hMARK3-UBA can bind to four types of tetraubiquitin chains: M1, K11, K27, and K63. To confirm the reliability of this binding, we constructed hMARK3-UBA mutant proteins, and the results showed that the mutants lost the ability to bind to M1-linked ubiquitin chains."