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Proc Natl Acad Sci U S A. 2008 Feb 12;105(6):2198-202. doi: 10.1073/pnas.0711074105. Epub 2008 Feb 11.

Remodeling of ryanodine receptor complex causes "leaky" channels: a molecular mechanism for decreased exercise capacity.

Author information

1
Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.

Abstract

During exercise, defects in calcium (Ca2+) release have been proposed to impair muscle function. Here, we show that during exercise in mice and humans, the major Ca2+ release channel required for excitation-contraction coupling (ECC) in skeletal muscle, the ryanodine receptor (RyR1), is progressively PKA-hyperphosphorylated, S-nitrosylated, and depleted of the phosphodiesterase PDE4D3 and the RyR1 stabilizing subunit calstabin1 (FKBP12), resulting in "leaky" channels that cause decreased exercise tolerance in mice. Mice with skeletal muscle-specific calstabin1 deletion or PDE4D deficiency exhibited significantly impaired exercise capacity. A small molecule (S107) that prevents depletion of calstabin1 from the RyR1 complex improved force generation and exercise capacity, reduced Ca2+-dependent neutral protease calpain activity and plasma creatine kinase levels. Taken together, these data suggest a possible mechanism by which Ca2+ leak via calstabin1-depleted RyR1 channels leads to defective Ca2+ signaling, muscle damage, and impaired exercise capacity.

PMID:
18268335
PMCID:
PMC2538898
DOI:
10.1073/pnas.0711074105
[Indexed for MEDLINE]
Free PMC Article

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