REVIEW: Troponin: Structure, Properties, and Mechanism of Functioning

V. L. Filatov^1*, A. G. Katrukha², T. V. Bulargina¹, and N. B. Gusev³

¹Department of Bioorganic Chemistry, School of Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-2788; E-mail: filatov@soil.msu.ru

²Moscow Scientific-Research Institute of Medical Ecology, Simferopolskii Bulvar 8, Moscow, 113149 Russia; fax: (095) 939-2788; E-mail: katrukha@soil.msu.ru

³Department of Biochemistry, School of Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-3955; E-mail: gusev@gusev.bio.msu.su

^* To whom correspondence should be addressed.

Received March 22, 1999; Revision received April 28, 1999

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This review discusses the structure and properties of the isolated components of troponin, their interaction, and the mechanisms of regulation of contractile activity of skeletal and cardiac muscle. Data on the structure of troponin C in crystals and in solution are presented. The Ca²⁺-induced conformational changes of troponin C structure are described. The structure of troponin I is analyzed and its interaction with other components of actin filaments is discussed. Data on phosphorylation of troponin I by various protein kinases are presented. The role of troponin I phosphorylation in the regulation of contractile activity of the heart is analyzed. The structural properties of troponin T and its interaction with other components of thin filaments are described. Data on the phosphorylation of troponin T are presented and the effect of troponin T phosphorylation on contractile activity of different muscles is discussed. Modern models of the functioning of troponin are presented and analyzed.

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KEY WORDS: troponin, tropomyosin, actin, regulation of muscle contraction

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