Cryo-electron tomography of cardiac myofibrils reveals a 3D lattice spring within the Z-discs.
Commun Biol
; 3(1): 585, 2020 10 16.
Article
in En
| MEDLINE
| ID: mdl-33067529
ABSTRACT
The Z-disc forms a boundary between sarcomeres, which constitute structural and functional units of striated muscle tissue. Actin filaments from adjacent sarcomeres are cross-bridged by α-actinin in the Z-disc, allowing transmission of tension across the myofibril. Despite decades of studies, the 3D structure of Z-disc has remained elusive due to the limited resolution of conventional electron microscopy. Here, we observed porcine cardiac myofibrils using cryo-electron tomography and reconstructed the 3D structures of the actin-actinin cross-bridging complexes within the Z-discs in relaxed and activated states. We found that the α-actinin dimers showed contraction-dependent swinging and sliding motions in response to a global twist in the F-actin lattice. Our observation suggests that the actin-actinin complex constitutes a molecular lattice spring, which maintains the integrity of the Z-disc during the muscle contraction cycle.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Electron Microscope Tomography
/
Myocardium
/
Myofibrils
Limits:
Animals
Language:
En
Journal:
Commun Biol
Year:
2020
Document type:
Article
Affiliation country:
Japón