RT Journal Article SR Electronic T1 K29-Linked Ubiquitin Signaling Regulates Proteotoxic Stress Response and Cell Cycle JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.10.15.341719 DO 10.1101/2020.10.15.341719 A1 Yuanyuan Yu A1 Qingyun Zheng A1 Satchal K. Erramilli A1 Man Pan A1 Seongjin Park A1 Yuan Xie A1 Jingxian Li A1 Jingyi Fei A1 Anthony A. Kossiakoff A1 Lei Liu A1 Minglei Zhao YR 2021 UL http://biorxiv.org/content/early/2021/04/10/2020.10.15.341719.abstract AB Protein ubiquitination shows remarkable topological and functional diversity through the polymerization of ubiquitin via different linkages. Deciphering the cellular ubiquitin code is of central importance to understand the physiology of the cell. Among the eight possible linkages, K29-linked polyubiquitin is a relatively abundant type of polyubiquitin in both human and yeast cells. However, our understanding of its function is rather limited due to the lack of specific binders as tools to detect K29-linked polyubiquitin. In this study, we screened and characterized a synthetic antigen-binding fragment, termed sAB-K29, that can specifically recognize K29-linked polyubiquitin using chemically synthesized K29-linked diubiquitin. We further determined the crystal structure of this fragment bound to the K29-linked diubiquitin, which revealed the molecular basis of specificity. Using sAB-K29 as a tool, we uncovered that K29-linked ubiquitination is involved in different kinds of cellular proteotoxic stress response as well as cell cycle regulation. In particular, we showed that K29-linked ubiquitination is enriched in the midbody and downregulation of the K29-linked ubiquitination signal arrests cells in G1/S phase.Competing Interest StatementThe authors have declared no competing interest.