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Aspholm EE, Lidman J, Burmann BM. Structural basis of substrate recognition and allosteric activation of the proapoptotic mitochondrial HtrA2 protease. Nat Commun 2024; 15:4592. [PMID: 38816423 DOI: 10.1038/s41467-024-48997-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/14/2024] [Indexed: 06/01/2024] Open
Abstract
The mitochondrial serine protease HtrA2 is a human homolog of the Escherichia coli Deg-proteins exhibiting chaperone and proteolytic roles. HtrA2 is involved in both apoptotic regulation via its ability to degrade inhibitor-of-apoptosis proteins (IAPs), as well as in cellular maintenance as part of the cellular protein quality control machinery, by preventing the possible toxic accumulation of aggregated proteins. In this study, we use advanced solution NMR spectroscopy methods combined with biophysical characterization and biochemical assays to elucidate the crucial role of the substrate recognizing PDZ domain. This domain regulates the protease activity of HtrA2 by triggering an intricate allosteric network involving the regulatory loops of the protease domain. We further show that divalent metal ions can both positively and negatively modulate the activity of HtrA2, leading to a refined model of HtrA2 regulation within the apoptotic pathway.
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Affiliation(s)
- Emelie E Aspholm
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Göteborg, Sweden
| | - Jens Lidman
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Göteborg, Sweden
| | - Björn M Burmann
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden.
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Göteborg, Sweden.
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Lidman J, Sallova Y, Matečko-Burmann I, Burmann BM. Structure and dynamics of the mitochondrial DNA-compaction factor Abf2 from S. cerevisiae. J Struct Biol 2023; 215:108008. [PMID: 37543301 DOI: 10.1016/j.jsb.2023.108008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 07/10/2023] [Accepted: 08/02/2023] [Indexed: 08/07/2023]
Abstract
Mitochondria are essential organelles that produce most of the energy via the oxidative phosphorylation (OXPHOS) system in all eukaryotic cells. Several essential subunits of the OXPHOS system are encoded by the mitochondrial genome (mtDNA) despite its small size. Defects in mtDNA maintenance and expression can lead to severe OXPHOS deficiencies and are amongst the most common causes of mitochondrial disease. The mtDNA is packaged as nucleoprotein structures, referred to as nucleoids. The conserved mitochondrial proteins, ARS-binding factor 2 (Abf2) in the budding yeast Saccharomyces cerevisiae (S. cerevisiae) and mitochondrial transcription factor A (TFAM) in mammals, are nucleoid associated proteins (NAPs) acting as condensing factors needed for packaging and maintenance of the mtDNA. Interestingly, gene knockout of Abf2 leads, in yeast, to the loss of mtDNA and respiratory growth, providing evidence for its crucial role. On a structural level, the condensing factors usually contain two DNA binding domains called high-mobility group boxes (HMG boxes). The co-operating mechanical activities of these domains are crucial in establishing the nucleoid architecture by bending the DNA strands. Here we used advanced solution NMR spectroscopy methods to characterize the dynamical properties of Abf2 together with its interaction with DNA. We find that the two HMG-domains react notably different to external cues like temperature and salt, indicating distinct functional properties. Biophysical characterizations show the pronounced difference of these domains upon DNA-binding, suggesting a refined picture of the Abf2 functional cycle.
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Affiliation(s)
- Jens Lidman
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Göteborg, Sweden
| | - Ylber Sallova
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Göteborg, Sweden
| | - Irena Matečko-Burmann
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Göteborg, Sweden; Department of Psychiatry and Neurochemistry, University of Gothenburg, 405 30 Göteborg, Sweden
| | - Björn M Burmann
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Göteborg, Sweden.
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Šimčíková D, Gelles-Watnick S, Neugebauer KM. Tudor-dimethylarginine interactions: the condensed version. Trends Biochem Sci 2023; 48:689-698. [PMID: 37156649 PMCID: PMC10524826 DOI: 10.1016/j.tibs.2023.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 05/10/2023]
Abstract
Biomolecular condensates (BMCs) can facilitate or inhibit diverse cellular functions. BMC formation is driven by noncovalent protein-protein, protein-RNA, and RNA-RNA interactions. Here, we focus on Tudor domain-containing proteins - such as survival motor neuron protein (SMN) - that contribute to BMC formation by binding to dimethylarginine (DMA) modifications on protein ligands. SMN is present in RNA-rich BMCs, and its absence causes spinal muscular atrophy (SMA). SMN's Tudor domain forms cytoplasmic and nuclear BMCs, but its DMA ligands are largely unknown, highlighting open questions about the function of SMN. Moreover, DMA modification can alter intramolecular interactions and affect protein localization. Despite these emerging functions, the lack of direct methods of DMA detection remains an obstacle to understanding Tudor-DMA interactions in cells.
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Affiliation(s)
- Daniela Šimčíková
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Sara Gelles-Watnick
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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Molina JA, Galaz-Davison P, Komives EA, Artsimovitch I, Ramírez-Sarmiento CA. Allosteric couplings upon binding of RfaH to transcription elongation complexes. Nucleic Acids Res 2022; 50:6384-6397. [PMID: 35670666 PMCID: PMC9226497 DOI: 10.1093/nar/gkac453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 05/07/2022] [Accepted: 05/18/2022] [Indexed: 12/03/2022] Open
Abstract
In every domain of life, NusG-like proteins bind to the elongating RNA polymerase (RNAP) to support processive RNA synthesis and to couple transcription to ongoing cellular processes. Structures of factor-bound transcription elongation complexes (TECs) reveal similar contacts to RNAP, consistent with a shared mechanism of action. However, NusG homologs differ in their regulatory roles, modes of recruitment, and effects on RNA synthesis. Some of these differences could be due to conformational changes in RNAP and NusG-like proteins, which cannot be captured in static structures. Here, we employed hydrogen-deuterium exchange mass spectrometry to investigate changes in local and non-local structural dynamics of Escherichia coli NusG and its paralog RfaH, which have opposite effects on expression of xenogenes, upon binding to TEC. We found that NusG and RfaH regions that bind RNAP became solvent-protected in factor-bound TECs, whereas RNAP regions that interact with both factors showed opposite deuterium uptake changes when bound to NusG or RfaH. Additional changes far from the factor-binding site were observed only with RfaH. Our results provide insights into differences in structural dynamics exerted by NusG and RfaH during binding to TEC, which may explain their different functional outcomes and allosteric regulation of transcriptional pausing by RfaH.
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Affiliation(s)
- José Alejandro Molina
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Pablo Galaz-Davison
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - César A Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
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Kawale AA, Burmann BM. Characterization of backbone dynamics using solution NMR spectroscopy to discern the functional plasticity of structurally analogous proteins. STAR Protoc 2021; 2:100919. [PMID: 34761231 PMCID: PMC8567434 DOI: 10.1016/j.xpro.2021.100919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2022] Open
Abstract
The comprehensive delineation of inherent dynamic motions embedded in proteins, which can be crucial for their functional repertoire, is often essential yet remains poorly understood in the majority of cases. In this protocol, we outline detailed descriptions of the necessary steps for employing solution NMR spectroscopy for the in-depth amino acid level understanding of backbone dynamics of proteins. We describe the application of the protocol on the structurally analogous Tudor domains with disparate functionalities as a model system. For complete details on the use and execution of this protocol, please refer to Kawale and Burmann (2021).
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Affiliation(s)
- Ashish A Kawale
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Gothenburg, Sweden.,Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Björn M Burmann
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, 405 30 Gothenburg, Sweden.,Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
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