Most, P. et al. (2003) The C terminus (amino acids 75-94) and the linker region (amino acids 42-54) of the Ca2+-binding protein S100A1 differentially enhance sarcoplasmic Ca2+ release in murine skinned skeletal muscle fibers. Journal of Biological Chemistry, 278(29), pp. 26356-26364. (doi: 10.1074/jbc.M303338200)
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Abstract
S100A1, a Ca2+-binding protein of the EF-hand type, is most highly expressed in striated muscle and has previously been shown to interact with the skeletal muscle sarcoplasmic reticulum (SR) Ca2+ release channel/ryanodine receptor (RyR1) isoform. However, it was unclear whether S100A1/RyR1 interaction could modulate SR Ca2+ handling and contractile properties in skeletal muscle fibers. Since S100A1 protein is differentially expressed in fast- and slow-twitch skeletal muscle, we used saponin-skinned murine Musculus extensor digitorum longus (EDL) and Musculus soleus (Soleus) fibers to assess the impact of S100A1 protein on SR Ca2+ release and isometric twitch force in functionally intact permeabilized muscle fibers. S100A1 equally enhanced caffeine-induced SR Ca2+ release and Ca2+-induced isometric force transients in both muscle preparations in a dose-dependent manner. Introducing a synthetic S100A1 peptide model (devoid of EF-hand Ca2+-binding sites) allowed identification of the S100A1 C terminus (amino acids 75-94) and hinge region (amino acids 42 54) to differentially enhance SR Ca2+ release with a nearly 3-fold higher activity of the C terminus. These effects were exclusively based on enhanced SR Ca2+ release as S100A1 influenced neither SR Ca2+ uptake nor myofilament Ca2+ sensitivity/cooperativity in our experimental setting. In conclusion, our study shows for the first time that S100A1 augments contractile performance both of fast- and slow-twitch skeletal muscle fibers based on enhanced SR Ca2+ efflux at least mediated by the C terminus of S100A1 protein. Thus, our data suggest that S100A1 may serve as an endogenous enhancer of SR Ca2+ release and might therefore be of physiological relevance in the process of excitation-contraction coupling in skeletal muscle.
Item Type: | Articles |
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Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Smith, Professor Godfrey |
Authors: | Most, P., Remppis, A., Weber, C., Bernotat, J., Ehlermann, P., Pleger, S., Kirsch, W., Weber, M., Uttenweiler, D., Smith, G., Katus, H., and Fink, R. |
College/School: | College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health College of Medical Veterinary and Life Sciences |
Journal Name: | Journal of Biological Chemistry |
Journal Abbr.: | J Biol Chem. |
Publisher: | American Society for Biochemistry and Molecular Biology, Inc. |
ISSN: | 0021-9258 |
ISSN (Online): | 1083-351X |
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