PUBLICATION
Non-Ca2+-conducting Ca2+ channels in fish skeletal muscle excitation-contraction coupling
- Authors
- Schredelseker, J., Shrivastav, M., Dayal, A., and Grabner, M.
- ID
- ZDB-PUB-100317-10
- Date
- 2010
- Source
- Proceedings of the National Academy of Sciences of the United States of America 107(12): 5658-5663 (Journal)
- Registered Authors
- Dayal, Anamika, Grabner, Manfred, Schredelseker, Johann
- Keywords
- calcium conductivity, evolution, ion channels, slow and fast muscle, zebrafish
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Calcium Channels, L-Type/chemistry
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism*
- Evolution, Molecular
- Excitation Contraction Coupling
- Fishes/genetics
- Fishes/physiology*
- In Vitro Techniques
- Molecular Sequence Data
- Muscle Contraction/physiology
- Muscle, Skeletal/physiology*
- Patch-Clamp Techniques
- Phylogeny
- Protein Isoforms/chemistry
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- Protein Subunits
- Ryanodine Receptor Calcium Release Channel/chemistry
- Ryanodine Receptor Calcium Release Channel/genetics
- Ryanodine Receptor Calcium Release Channel/metabolism
- Sequence Homology, Amino Acid
- Species Specificity
- Tissue Distribution
- Zebrafish/genetics
- Zebrafish/physiology*
- Zebrafish Proteins/chemistry
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism*
- PubMed
- 20212109 Full text @ Proc. Natl. Acad. Sci. USA
Citation
Schredelseker, J., Shrivastav, M., Dayal, A., and Grabner, M. (2010) Non-Ca2+-conducting Ca2+ channels in fish skeletal muscle excitation-contraction coupling. Proceedings of the National Academy of Sciences of the United States of America. 107(12):5658-5663.
Abstract
During skeletal muscle excitation-contraction (EC) coupling, membrane depolarizations activate the sarcolemmal voltage-gated L-type Ca(2+) channel (Ca(V)1.1). Ca(V)1.1 in turn triggers opening of the sarcoplasmic Ca(2+) release channel (RyR1) via interchannel protein-protein interaction to release Ca(2+) for myofibril contraction. Simultaneously to this EC coupling process, a small and slowly activating Ca(2+) inward current through Ca(V)1.1 is found in mammalian skeletal myotubes. The role of this Ca(2+) influx, which is not immediately required for EC coupling, is still enigmatic. Interestingly, whole-cell patch clamp experiments on freshly dissociated skeletal muscle myotubes from zebrafish larvae revealed the lack of such Ca(2+) currents. We identified two distinct isoforms of the pore-forming Ca(V)1.1alpha(1S) subunit in zebrafish that are differentially expressed in superficial slow and deep fast musculature. Both do not conduct Ca(2+) but merely act as voltage sensors to trigger opening of two likewise tissue-specific isoforms of RyR1. We further show that non-Ca(2+) conductivity of both Ca(V)1.1alpha(1S) isoforms is a common trait of all higher teleosts. This non-Ca(2+) conductivity of Ca(V)1.1 positions teleosts at the most-derived position of an evolutionary trajectory. Though EC coupling in early chordate muscles is activated by the influx of extracellular Ca(2+), it evolved toward Ca(V)1.1-RyR1 protein-protein interaction with a relatively small and slow influx of external Ca(2+) in tetrapods. Finally, the Ca(V)1.1 Ca(2+) influx was completely eliminated in higher teleost fishes.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping