ArticleVan der Pijl RJ, Ma W, Lewis CTA, Haar L, Buhl A, Farman GP, Rhodehamel M, Jani VP, Nelson OL, Zhang C, Granzier H, Ochala J.
Mol Metab. 2025 Feb;92:102084.
AIM: The aim of the present study was to define whether cardiac myosin contributes to energy conservation in the heart of hibernating mammals.
METHODS: Thin cardiac strips were isolated from the left ventricles of active and hibernating grizzly bears; and subjected to loaded Mant-ATP chase assays, X-ray diffraction and proteomics.
MAIN FINDINGS: Hibernating grizzly bears displayed an unusually high proportion of ATP-conserving super-relaxed cardiac myosin molecules that are likely due to altered levels of phosphorylation and rod region stability.
CONCLUSIONS: Cardiac myosin depresses the heart's energetic demand during hibernation by modulating its function.