CKIP‐1 couples Smurf1 ubiquitin ligase with Rpt6 subunit of proteasome to promote substrate degradation |
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| Authors: | Yiwu Wang Luo Zhang Kefeng Lu Guichun Xing Ping Xie Fuchu He Lingqiang Zhang |
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| Affiliation: | 1. State Key Laboratory of Proteomics, Department of Genomics and Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, , Beijing, 100850, China;2. National Engineering Research Center for Protein Drugs;3. College of Life Science and Bioengineering, Beijing University of Technology;4. Institute of Cancer Stem Cell, Dalian Medical University, , Dalian, Liaoning Province, 116044 China |
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| Abstract: | ![]()
CKIP‐1 is an activator of the Smurf1 ubiquitin ligase acting to promote the ubiquitylation of Smad5 and MEKK2. The mechanisms involved in the recognition and degradation of these substrates by the proteasome remain unclear. Here, we show that CKIP‐1, through its leucine zipper, interacts directly with the Rpt6 ATPase of the 19S regulatory particle of the proteasome. CKIP‐1 mediates the Smurf1–Rpt6 interaction and delivers the ubiquitylated substrates to the proteasome. Depletion of CKIP‐1 reduces the degradation of Smurf1 and its substrates by Rpt6. These findings reveal an unexpected adaptor role of CKIP‐1 in coupling the ubiquitin ligase and the proteasome. |
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| Keywords: | proteasome ubiquitin ligase Smurf1 Rpt6 adaptor protein |
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