Nanobodies combined with DNA-PAINT super-resolution reveal a staggered titin nano-architecture in flight muscles
- Max Planck Institute of Biochemistry, Germany
- Aix Marseille University, CNRS, IDBM, France
- Max Planck Institute for Multidisciplinary Sciences, Germany
- Ludwig Maximilian University, Germany
Abstract
Sarcomeres are the force producing units of all striated muscles. Their nanoarchitecture critically depends on the large titin protein, which in vertebrates spans from the sarcomeric Z-disc to the M-band and hence links actin and myosin filaments stably together. This ensures sarcomeric integrity and determines the length of vertebrate sarcomeres. However, the instructive role of titins for sarcomeric architecture outside of vertebrates is not as well understood. Here, we used a series of nanobodies, the Drosophila titin nanobody toolbox, recognising specific domains of the two Drosophila titin homologs Sallimus and Projectin to determine their precise location in intact flight muscles. By combining nanobodies with DNA-PAINT super-resolution microscopy, we found that, similar to vertebrate titin, Sallimus bridges across the flight muscle I-band, whereas Projectin is located at the beginning of the A-band. Interestingly, the ends of both proteins overlap at the I-band/A-band border, revealing a staggered organisation of the two Drosophila titin homologs. This architecture may help to stably anchor Sallimus at the myosin filament and hence ensure efficient force transduction during flight.
Data availability
All source data for all figures are provided.Figure 3 - Source Data 1Figure 4 - Source Data 1Figure 5 - Source Data 1Figure 6 - Source Data 1All new code has been uploaded to a public database and the link is provided.
Article and author information
Author details
Funding
Centre National de la Recherche Scientifique
- Frank Schnorrer
Human Frontier Science Program (RGP0052/2018)
- Frank Schnorrer
Agence Nationale de la Recherche (ANR-10-INBS-04-01)
- Frank Schnorrer
Agence Nationale de la Recherche (ANR-16-CONV-0001,Turing Centre for Living Systems)
- Frank Schnorrer
Aix-Marseille Université
- Pierre Mangeol
Max-Planck-Gesellschaft
- Dirk Görlich
Max-Planck-Gesellschaft
- Ralf Jungmann
European Research Council (ERC-2019-SyG 856118)
- Dirk Görlich
European Research Council (ERC-2019-SyG 856118)
- Frank Schnorrer
European Research Council (ERC-2015-StG 680241)
- Ralf Jungmann
Aix-Marseille Université (ANR-11-IDEX-0001-02)
- Frank Schnorrer
Agence Nationale de la Recherche (ACHN MUSCLE-FORCES)
- Frank Schnorrer
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2023, Schueder et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Nanobodies combined with DNA-PAINT super-resolution reveal a staggered titin nano-architecture in flight muscles
eLife 12:e79344.
https://doi.org/10.7554/eLife.79344
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