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.
Metrics
-
- 2,523
- views
-
- 338
- downloads
-
- 15
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
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
Further reading
-
- Cell Biology
- Developmental Biology
In most murine species, spermatozoa exhibit a falciform apical hook at the head end. The function of the sperm hook is not yet clearly understood. In this study, we investigate the role of the sperm hook in the migration of spermatozoa through the female reproductive tract in Mus musculus (C57BL/6), using a deep tissue imaging custom-built two-photon microscope. Through live reproductive tract imaging, we found evidence indicating that the sperm hook aids in the attachment of spermatozoa to the epithelium and facilitates interactions between spermatozoa and the epithelium during migration in the uterus and oviduct. We also observed synchronized sperm beating, which resulted from the spontaneous unidirectional rearrangement of spermatozoa in the uterus. Based on live imaging of spermatozoa-epithelium interaction dynamics, we propose that the sperm hook plays a crucial role in successful migration through the female reproductive tract by providing anchor-like mechanical support and facilitating interactions between spermatozoa and the female reproductive tract in the house mouse.
-
- Developmental Biology
The morphogen FGF8 establishes graded positional cues imparting regional cellular responses via modulation of early target genes. The roles of FGF signaling and its effector genes remain poorly characterized in human experimental models mimicking early fetal telencephalic development. We used hiPSC-derived cerebral organoids as an in vitro platform to investigate the effect of FGF8 signaling on neural identity and differentiation. We found that FGF8 treatment increases cellular heterogeneity, leading to distinct telencephalic and mesencephalic-like domains that co-develop in multi-regional organoids. Within telencephalic regions, FGF8 affects the anteroposterior and dorsoventral identity of neural progenitors and the balance between GABAergic and glutamatergic neurons, thus impacting spontaneous neuronal network activity. Moreover, FGF8 efficiently modulates key regulators responsible for several human neurodevelopmental disorders. Overall, our results show that FGF8 signaling is directly involved in both regional patterning and cellular diversity in human cerebral organoids and in modulating genes associated with normal and pathological neural development.
