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Title | Cryo-electron tomography of cardiac myofibrils reveals a 3D lattice spring within the Z-discs. |
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Journal, issue, pages | Commun Biol, Vol. 3, Issue 1, Page 585, Year 2020 |
Publish date | Oct 16, 2020 |
![]() | Toshiyuki Oda / Haruaki Yanagisawa / ![]() |
PubMed 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 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. |
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Methods | EM (subtomogram averaging) |
Resolution | 23.0 Å |
Structure data | ![]() EMDB-30242: ![]() EMDB-30243: |
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