Related Experiment Video
Updated: May 28, 2026
08:37
Purification of the Sarco-Endoplasmic Reticulum Ca2+-ATPase from Rabbit Muscle
Published on: March 21, 2025
Cylindrical Crystallization of Ca2+-ATPase and Its Potential Role in Sarcoplasmic Reticulum Dynamics
Jun Nakamura1, Genichi Tajima2, Makiko Suwa3
1Jun Nakamura Institute, Moniwa-dai 2-3-21, Taihaku-ku, Sendai-shi, Miyagi 982-0252, Japan.
International Journal of Molecular Sciences
|May 27, 2026
Summary
Sarcoplasmic reticulum (SR) membrane proteins may form dynamic crystalline networks. This "endoskeletal motor" influences SR vesicle shape and movement, potentially coordinating muscle contraction.
Area of Science:
- Muscle physiology
- Molecular cell biology
- Biophysics
Background:
- Skeletal muscle contraction relies on coordinated calcium release.
- Ryanodine receptors (RyRs) are key calcium channels in muscle.
- The mechanical interactions within the sarcoplasmic reticulum (SR) are not fully understood.
Purpose of the Study:
- To review the proposed
- mechanical sarcoplasmic reticulum (SR) paradigm
- for understanding RyR function and muscle contraction.
Main Methods:
- Cryo-electron tomography of RyR and Ca2+ channels at the T-tubule/SR junction.
- Negative staining and transmission electron microscopy of SR vesicles.
- Analysis of Ca2+-ATPase (ATPase) molecular arrangements.
Main Results:
- Ca2+-ATPase (ATPase) molecules form dynamic cylindrical crystals in the SR membrane.
- ATP and cytoplasmic calcium levels regulate ATPase crystal formation and SR vesicle shape.
- Elongated SR vesicles transform into round forms via reversible ATPase crystal collapse.
Conclusions:
- The dynamic crystalline network of ATPase molecules acts as an
- SR membrane-endoskeletal motor
- manipulating SR movement.
- This mechanism may contribute to the synchronized opening of RyRs for muscle contraction.
- Interactions between ATPase and RyR crystals are proposed.
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