Summary
Troponin C (TnC) was extracted from bundles of rat and mouse skinned cardiac ventricular cells by a method similar to that previously used to extract TnC from skinned rabbit skeletal muscle cells (Kerricket al., J. biol. Chem. 260, 15687-93, 1985) and replaced with either bovine cardiac or rabbit fast-twitch skeletal TnC. In contrast, the same TnC extraction conditions will not extract TnC from either bovine or rabbit cardiac skinned fibres. When the extracted TnC was replaced by bovine cardiac TnC the Sr2+-activated tension relationship was not altered from control values. In contrast, replacement of the endogenous TnC with exogenous rabbit fast-twitch TnC caused the relationship between Sr2+ concentration and tension to shift towards higher concentrations of Sr2+. The Sr2+-activated tension of rat fibres with fast-twitch TnC was identical to that of rabbit fast-twitch skinned fibres. Partial skeletal TnC substitution in skinned cardiac cells gradually shifted the relationship between tension and [Sr2+] to higher Sr2+ concentrations and caused the cells to be activated over a wider range of Sr2+ concentrations. Thus it appears that the activation of rat cardiac skinned cells by Sr2+ is determined by characteristics of the TnC. In contrast, the Sr2+ activation of skinned rabbit fast-twitch skeletal fibres containing either cardiac or skeletal TnC is identical, strongly suggesting that protein-protein interactions determined the Sr2+-activation properties in these fibres.
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References
Babu, A. &Gulati, J. (1986) The control of cardiac muscle contraction with fast-twitch muscle troponin-C (TNC).Biophys. J. 49, 83a.
Babu, A., Scordilis, S. P., Sonnenblick, E. H. &Gulati, J. (1987) The control of myocardial contraction with skeletal fast muscle troponin C.J. biol. Chem. 262, 5815–22.
Best, P. M., Donaldson, S. K. B. &Kerrick, W. G. L. (1977) Tension in mechanically disrupted mammalian cardiac cells: Effects of magnesium adenosine triphosphate.J. Physiol. (lond.) 265, 1–77.
Brandt. P. W., Cox, R. N., Kawai, M. &Robinson, T. (1982) Regulation of tension in skinned muscle fibers: Effect of crossbridge kinetics on apparent Ca2+ sensitivity.J. gen. Physiol. 79, 997–1016.
Brandt, P. W., Diamond, M. S., Gluck, B., Kawai, M. &Schachat, F. (1984) Molecular basis of cooperativity in vertebrate muscle thin filaments.Carlsberg Res. Commun. 49, 155–67
Cox, J. A., Comte, M. &Stein, E. A. (1981) Calmodulinfree skeletal-muscle troponin C prepared in the absence of urea.Biochem. J. 195, 205–11.
Donaldson, S. K. B. &Kerrick, W. G. L. (1975) Characterization of the effects of Mg2+ on Ca2+- and Sr2+-activated tension generation of skinned skeletal muscle fibers.J. gen. Physiol. 66, 427–44
Ebashi, S., Kodama, A. &Ebashi, F. (1968) Troponin: I. Preparation and physiological function.J. Biochem. 64, 465–77.
Greaser, M. L. &Gergely, J. (1971) Reconstruction of troponin activity from three protein components.J. biol. Chem. 246, 4226–33.
Hellam, D. C. &Podolsky, R. J. (1969) Force measurements in skinned muscle fibres.J. Physiol. (Lond.) 200, 807–19.
Hill, A. V. (1913) The combinations of haemglobin with oxygen and with carbon monoxide.Biochem. J. 7, 471–80.
Hill, T. L., Eisenberg, E. &Greene, L. E. (1983) Alternate model for the cooperative equilibrium binding of myosin subfragment-1-nucleotide complex to actin-troponin-tropomyosin.Proc. natl. Acad. Sci. USA 80, 60–4.
Holroyde, M. J., Robertson, S. P., Johnson, J. D. Solaro, R. J. &Potter, J. D. (1980) The calcium and magnesium sites on cardiac troponin and their role in the regulation of myofibrillar adenosine triphosphatase.J. biol. Chem. 255, 11688–93.
Kerrick, W. G. L. &Krasner, B. (1975) Disruption of the sarcolemma of mammalian skeletal muscle fibers by homogenization.J. appl. Physiol. 39, 1052–5.
Kerrick, W. G. L., Malencik, D. A., Hoar, P. E., Potter, J. D., Coby, R. L., Pocinwong, S. &Fischer, E. H. (1980) Ca2+ and Sr2+ activation: Comparison of cardiac and skeletal muscle contraction models.Pflügers Arch. 386, 207–13.
Kerrick, W. G. L., Zot, H. G., Hoar, P. E. &Potter, J. D. (1985) Evidence that the Sr2+ activation properties of cardiac troponin C are altered when substituted into skinned skeletal muscle fibres.J. biol. Chem. 260, 15687–93.
Laemmli, U. K. (1970) Cleavage of structural proteins during the assembly of the head of bacteriophage T4.Nature 227, 680–5.
Leavis, P. C. &Kraft, E. L. (1978) Calcium binding to cardiac troponin C.Archiv. Biochem. Biophys. 186, 411–15.
Moss, R. L., Giulian, G. G. &Greaser, M. L. (1985) The effects of partial extraction of TnC upon the tension-pCa relationship in rabbit skinned skeletal muscle fibers.J. gen. Physiol. 86, 585–600.
Moss, R. L., Giulian, G. G. &Greaser, M. L. (1985) The effects of partial extraction of TnC upon the tension-pCa relationship in rabbit skinned muscle fibers.J. gen. Physiol. 86, 585–600.
Moss, R. L., Lauer, M. R., Giulian, G. G. &Greaser, M. L. (1986) Altered Ca2+ dependence of tension development in skinned skeletal muscle fibers following modification of troponin by partial substitution with cardiac troponin C.J. biol. Chem. 261, 6096–9.
Potter, J. D. (1982) Preparation of troponin and its subunits from rabbit skeletal and bovine cardiac muscle.Methods in Enzymology 85, 241–63.
Potter, J. D. &Gergely, J. (1975) The calcium and magnesium binding sites on troponin and their role in the regulation of myofibrillar adenosine triphosphatase.J. biol. Chem. 250, 4628–33.
Van Eerd, J. P. &Takahashi, K. (1976) Determination of the complete amino acid sequence of bovine cardiac troponin C.Biochem. USA 15, 1171–80.
Zot, H. G. &Potter, J. D. (1982) A structural role of the Ca2+-Mg2+ sites on troponin C in the regulation of muscle contraction: Preparation and properties of troponin C depleted myofibrils.J. biol. Chem. 257, 7678–83.
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Hoar, P.E., Potter, J.D. & Kerrick, W.G.L. Skinned ventricular fibres: troponin C extraction is species-dependent and its replacement with skeletal troponin C changes Sr2+ activation properties. J Muscle Res Cell Motil 9, 165–173 (1988). https://doi.org/10.1007/BF01773738
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DOI: https://doi.org/10.1007/BF01773738