The molecular transition that confers voltage dependence to muscle contraction
Abstract What is the molecular origin of voltage dependence in skeletal muscle excitation-contraction? Cholinergic transmission to the muscle fiber triggers action potentials, which are sensed by voltage-gated L-type calcium channels (CaV1.1). In turn, the conformational changes in CaV1.1 propagate...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-05-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-025-59649-7 |
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| Summary: | Abstract What is the molecular origin of voltage dependence in skeletal muscle excitation-contraction? Cholinergic transmission to the muscle fiber triggers action potentials, which are sensed by voltage-gated L-type calcium channels (CaV1.1). In turn, the conformational changes in CaV1.1 propagate to and activate intracellular ryanodine receptors (RyR1), causing Ca2+ release and contraction. The CaV1.1 channel has four voltage-sensing domains (VSD-I to -IV) with diverse voltage-sensing properties, so the identity of VSD(s) responsible for conferring voltage dependence to RyR1 opening, is unknown. Using voltage-clamp fluorometry, we show that only VSD-III possesses kinetic, voltage-dependent and pharmacological properties consistent with skeletal-muscle excitability and Ca2+ release. We propose that the earliest voltage-dependent event in the excitation-contraction process is the structural rearrangement of VSD-III that propagates to RyR1 to initiate Ca2+ release and contraction. |
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| ISSN: | 2041-1723 |