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Bakti F, Stupperich H, Schmitt K, Valerius O, Köhler AM, Meister C, Strohdiek A, Harting R, Sasse C, Heimel K, Neumann P, Ficner R, Braus GH. Fungal COP9 signalosome assembly requires connection of two trimeric intermediates for integration of intrinsic deneddylase. Proc Natl Acad Sci U S A 2023; 120:e2305049120. [PMID: 37603767 PMCID: PMC10477865 DOI: 10.1073/pnas.2305049120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 08/01/2023] [Indexed: 08/23/2023] Open
Abstract
The conserved eight-subunit COP9 signalosome (CSN) is required for multicellular fungal development. The CSN deneddylase cooperates with the Cand1 exchange factor to control replacements of E3 ubiquitin cullin RING ligase receptors, providing specificity to eukaryotic protein degradation. Aspergillus nidulans CSN assembles through a heptameric pre-CSN, which is activated by integration of the catalytic CsnE deneddylase. Combined genetic and biochemical approaches provided the assembly choreography within a eukaryotic cell for native fungal CSN. Interactomes of functional GFP-Csn subunit fusions in pre-CSN deficient fungal strains were compared by affinity purifications and mass spectrometry. Two distinct heterotrimeric CSN subcomplexes were identified as pre-CSN assembly intermediates. CsnA-C-H and CsnD-F-G form independently of CsnB, which connects the heterotrimers to a heptamer and enables subsequent integration of CsnE to form the enzymatically active CSN complex. Surveillance mechanisms control accurate Csn subunit amounts and correct cellular localization for sequential assembly since deprivation of Csn subunits changes the abundance and location of remaining Csn subunits.
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Affiliation(s)
- Fruzsina Bakti
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Helena Stupperich
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Kerstin Schmitt
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Oliver Valerius
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Anna M. Köhler
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Cindy Meister
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Anja Strohdiek
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Rebekka Harting
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Christoph Sasse
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Kai Heimel
- Department of Microbial Cell Biology, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Piotr Neumann
- Department of Molecular Structural Biology, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Goettingen Center for Molecular Biosciences, University of Goettingen, 37077Goettingen, Germany
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