iScience (Apr 2020)

Ubiquitin Linkage Specificity of Deubiquitinases Determines Cyclophilin Nuclear Localization and Degradation

  • Yanchang Li,
  • Qiuyan Lan,
  • Yuan Gao,
  • Cong Xu,
  • Zhongwei Xu,
  • Yihao Wang,
  • Lei Chang,
  • Junzhu Wu,
  • Zixin Deng,
  • Fuchu He,
  • Daniel Finley,
  • Ping Xu

Journal volume & issue
Vol. 23, no. 4

Abstract

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Summary: Ubiquitin chain specificity has been described for some deubiquitinases (DUBs) but lacks a comprehensive profiling in vivo. We used quantitative proteomics to compare the seven lysine-linked ubiquitin chains between wild-type yeast and its 20 DUB-deletion strains, which may reflect the linkage specificity of DUBs in vivo. Utilizing the specificity and ubiquitination heterogeneity, we developed a method termed DUB-mediated identification of linkage-specific ubiquitinated substrates (DILUS) to screen the ubiquitinated lysine residues on substrates modified with certain chains and regulated by specific DUB. Then we were able to identify 166 Ubp2-regulating substrates with 244 sites potentially modified with K63-linked chains. Among these substrates, we further demonstrated that cyclophilin A (Cpr1) modified with K63-linked chain on K151 site was regulated by Ubp2 and mediated the nuclear translocation of zinc finger protein Zpr1. The K48-linked chains at non-K151 sites of Cpr1 were mainly regulated by Ubp3 and served as canonical signals for proteasome-mediated degradation. : Molecular Biology; Omics Subject Areas: Molecular Biology, Omics