Abstract
While it is now well known that a rise in the intracellular free Ca2+ concentration precedes muscle contraction, it is still puzzling how exactly the contractile machinery is switched on by calcium. Much progress was achieved, however, by studying the calcium-binding protein troponin, which proved to be the intracellular calcium switch regulating the activity of the contractile machinery in vertebrate striated muscle and many types of invertebrate muscle. Thus, troponin senses the free Ca2+ concentration in the myoplasm and transmits the calcium signal to the actin filaments (Sect.4.1). By influencing the filament structure troponin regulates potential crossbridge-binding sites on a segment of actin monomers and, hence, the activity of the contractile ATPase (Sect.4.2; cf. also Sect.10.2). This calcium activation may be modulated indirectly by ancillary calcium-binding proteins, such as calmodulin and parvalbumin and by the regulatory myosin light chains (Sect.4.3).
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© 1992 Springer-Verlag Berlin Heidelberg
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Rüegg, J.C. (1992). Calcium Binding and Regulatory Proteins. In: Calcium in Muscle Contraction. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-77560-4_5
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DOI: https://doi.org/10.1007/978-3-642-77560-4_5
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-77562-8
Online ISBN: 978-3-642-77560-4
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