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- In situ structures of muscle sarcomere and sarcomeric proteins
In situ structures of muscle sarcomere and sarcomeric proteins
Centre de recherche - Paris
Amphithéâtre Marie Curie
Pavillon Curie, 11 rue Pierre & Marie Curie, Paris 5ème
Description
Sarcomeres are force-generating and load-bearing devices of muscles. A precise molecular picture of how sarcomeres are built underpins understanding their role in health and diseases. We determined the molecular architecture of native skeletal and cardiac sarcomeres and structures of sarcomeric proteins using cryo-focused-ion-beam milling (cryo-FIB) and electron cryo-tomography (cryo-ET). Our three-dimensional reconstruction of the sarcomere reveals molecular details in the A-band, I-band and Z-disc and demonstrates the organisation of the thin and thick filaments and their cross-links [1,2]. Our reconstruction of the thick filament reveals the three-dimensional organization of myosin heads and tails, myosin-binding protein C (MyBP-C) and titin, elucidating the structural basis for their interaction during muscle contraction [2]. Using sub-tomogram averaging, we determined an in situ structure of a nebulous thin-filament-binding protein, nebulin, at 4.5 Ã… and demonstrated the molecular mechanism underlying its role as a "molecular ruler", in stabilising thin filament and in regulating myosin binding [3]. We also characterised the structure of a unique double-head myosin conformation, highlighting the inherent structural variability of myosin in muscle [1].
References
[1] Wang, Z, Grange M et al. (2021), Cell. 184,2135-2150.613
[2] Tamborrini, D et al. (2023), Nature, in press
[3]Â Wang, Z, Grange M et al. (2022), Science. 375, eabn1934
Organizers
Directeur de recherche Alexandre BAFFET
Institut Curie
Speakers
Stefan RAUNSER
Max Planck Institute of Molecular Physiology
Invited by
Anne HOUDUSSE
Institut Curie