Diana Cimiotti, Setsuko Fujita-Becker, Desirée Martha Möhner, Natalia Smolina, Heidi Budde, Aline Wies, Janine Morgenstern, Alexandra Gudkova, Thomas Sejersen, Gunnar Sjöberg, Andreas Mügge, Marc Michael Nowaczyk, Peter Reusch, Gabriele Pfitzer, Robert Stehle, Rasmus R. Schröder, Hans Georg Mannherz, Anna Kostareva, Kornelia Jaquet
- \(\it TNNI3\) encoding cTnI, the inhibitory subunit of the troponin complex, is the main target for mutations leading to restrictive cardiomyopathy (RCM). Here we investigate two cTnI-R170G/W amino acid replacements, identified in infantile RCM patients, which are located in the regulatory C-terminus of cTnI. The C-terminus is thought to modulate the function of the inhibitory region of cTnI. Both cTnI-R170G/W strongly enhanced the \(Ca^{2+}\)-sensitivity of skinned fibres, as is typical for RCM-mutations. Both mutants strongly enhanced the affinity of troponin (cTn) to tropomyosin compared to wildtype cTn, whereas binding to actin was either strengthened (R170G) or weakened (R170W). Furthermore, the stability of reconstituted thin filaments was reduced as revealed by electron microscopy. Filaments containing R170G/W appeared wavy and showed breaks. Decoration of filaments with myosin subfragment S1 was normal in the presence of R170W, but was irregular with R170G. Surprisingly, both mutants did not affect the \(Ca^{2+}\)-dependent activation of reconstituted cardiac thin filaments. In the presence of the N-terminal fragment of cardiac myosin binding protein C (cMyBPC-C0C2) cooperativity of thin filament activation was increased only when the filaments contained wildtype cTn. No effect was observed in the presence of cTn containing R170G/W. cMyBPC-C0C2 significantly reduced binding of wildtype troponin to actin/tropomyosin, but not of both mutant cTn. Moreover, we found a direct troponin/cMyBPC-C0C2 interaction using microscale thermophoresis and identified cTnI and cTnT, but not cTnC as binding partners for cMyBPC-C0C2. Only cTn containing cTnI-R170G showed a reduced affinity towards cMyBPC-C0C2. Our results suggest that the RCM cTnI variants R170G/W impair the communication between thin and thick filament proteins and destabilize thin filaments.
MetadatenAuthor: | Diana CimiottiORCiDGND, Setsuko Fujita-BeckerGND, Desirée Martha MöhnerGND, Natalia SmolinaGND, Heidi BuddeGND, Aline WiesGND, Janine MorgensternGND, Alexandra GudkovaGND, Thomas SejersenGND, Gunnar SjöbergGND, Andreas MüggeORCiDGND, Marc Michael NowaczykORCiDGND, Peter ReuschGND, Gabriele PfitzerGND, Robert StehleGND, Rasmus R. SchröderGND, Hans Georg MannherzGND, Anna KostarevaGND, Kornelia JaquetGND |
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URN: | urn:nbn:de:hbz:294-76819 |
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DOI: | https://doi.org/10.1371/journal.pone.0229227 |
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Parent Title (English): | PLoS ONE |
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Subtitle (English): | cTnI-R170G/W impair the interplay of sarcomeric proteins and the integrity of thin filaments |
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Publisher: | Public Library of Science |
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Place of publication: | San Francisco |
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Document Type: | Article |
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Language: | English |
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Date of Publication (online): | 2020/11/27 |
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Date of first Publication: | 2020/03/17 |
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Publishing Institution: | Ruhr-Universität Bochum, Universitätsbibliothek |
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Tag: | Open Access Fonds |
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Volume: | 15 |
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Issue: | 3, Article e0229227 |
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First Page: | e0229227-1 |
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Last Page: | e0229227-20 |
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Note: | Article Processing Charge funded by the Deutsche Forschungsgemeinschaft (DFG) and the Open Access Publication Fund of Ruhr-Universität Bochum. |
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Institutes/Facilities: | Arbeitsgruppe Molekulare Kardiologie |
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open_access (DINI-Set): | open_access |
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faculties: | Fakultät für Chemie und Biochemie |
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Licence (English): | Creative Commons - CC BY 4.0 - Attribution 4.0 International |
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