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Scinicariello S, Soderholm A, Schäfer M, Shulkina A, Schwartz I, Hacker K, Gogova R, Kalis R, Froussios K, Budroni V, Bestehorn A, Clausen T, Kovarik P, Zuber J, Versteeg GA. HUWE1 controls tristetraprolin proteasomal degradation by regulating its phosphorylation. eLife 2023; 12:e83159. [PMID: 36961408 PMCID: PMC10038661 DOI: 10.7554/elife.83159] [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: 09/01/2022] [Accepted: 02/26/2023] [Indexed: 03/25/2023] Open
Abstract
Tristetraprolin (TTP) is a critical negative immune regulator. It binds AU-rich elements in the untranslated-regions of many mRNAs encoding pro-inflammatory mediators, thereby accelerating their decay. A key but poorly understood mechanism of TTP regulation is its timely proteolytic removal: TTP is degraded by the proteasome through yet unidentified phosphorylation-controlled drivers. In this study, we set out to identify factors controlling TTP stability. Cellular assays showed that TTP is strongly lysine-ubiquitinated, which is required for its turnover. A genetic screen identified the ubiquitin E3 ligase HUWE1 as a strong regulator of TTP proteasomal degradation, which we found to control TTP stability indirectly by regulating its phosphorylation. Pharmacological assessment of multiple kinases revealed that HUWE1-regulated TTP phosphorylation and stability was independent of the previously characterized effects of MAPK-mediated S52/S178 phosphorylation. HUWE1 function was dependent on phosphatase and E3 ligase binding sites identified in the TTP C-terminus. Our findings indicate that while phosphorylation of S52/S178 is critical for TTP stabilization at earlier times after pro-inflammatory stimulation, phosphorylation of the TTP C-terminus controls its stability at later stages.
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Affiliation(s)
- Sara Scinicariello
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Adrian Soderholm
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Markus Schäfer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Alexandra Shulkina
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Irene Schwartz
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Kathrin Hacker
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Rebeca Gogova
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Robert Kalis
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Kimon Froussios
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Valentina Budroni
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Annika Bestehorn
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Tim Clausen
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
- Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Pavel Kovarik
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Johannes Zuber
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
- Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Gijs A Versteeg
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
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Ehrmann JF, Grabarczyk DB, Heinke M, Deszcz L, Kurzbauer R, Hudecz O, Shulkina A, Gogova R, Meinhart A, Versteeg GA, Clausen T. Structural basis for regulation of apoptosis and autophagy by the BIRC6/SMAC complex. Science 2023; 379:1117-1123. [PMID: 36758105 DOI: 10.1126/science.ade8873] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Inhibitor of apoptosis proteins (IAPs) bind to pro-apoptotic proteases, keeping them inactive and preventing cell death. The atypical ubiquitin ligase BIRC6 is the only essential IAP, additionally functioning as a suppressor of autophagy. We performed a structure-function analysis of BIRC6 in complex with caspase-9, HTRA2, SMAC, and LC3B, which are critical apoptosis and autophagy proteins. Cryo-electron microscopy structures showed that BIRC6 forms a megadalton crescent shape that arcs around a spacious cavity containing receptor sites for client proteins. Multivalent binding of SMAC obstructs client binding, impeding ubiquitination of both autophagy and apoptotic substrates. On the basis of these data, we discuss how the BIRC6/SMAC complex can act as a stress-induced hub to regulate apoptosis and autophagy drivers.
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Affiliation(s)
- Julian F Ehrmann
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Daniel B Grabarczyk
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Maria Heinke
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Luiza Deszcz
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Robert Kurzbauer
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Otto Hudecz
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Alexandra Shulkina
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter, Vienna, Austria
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Rebeca Gogova
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Anton Meinhart
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Gijs A Versteeg
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Tim Clausen
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
- Medical University of Vienna, Vienna, Austria
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