Reactome: A Curated Pathway Database
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Calcium Binds Troponin-C

Stable Identifier
R-HSA-390595
Type
Reaction
Species
Homo sapiens
Compartment
Locations in the PathwayBrowser
Summation

Troponin (Tn) is the central regulatory protein of striated muscle contraction. Tn consists of three components: troponin I (TNNI3; the inhibitor of actomyosin ATPase), Tn-T (which contains the binding site for tropomyosin) and troponin C (TNNC1, Tn-C). The binding of calcium to TNNC1 abolishes the inhibitory action of Tn on actin filaments. At the start of the striated muscle contraction cycle, a myosin head lacking a bound nucleotide is locked tightly onto an actin filament in a rigor conformation. TNNC1 binds four calcium ions. In an actively contracting muscle this state is very short-lived, being rapidly terminated by the binding of a molecule of ATP.

Literature References
PubMed ID Title Journal Year
10747208 Regulation of contraction in striated muscle Physiol Rev 2000
Regulatory Mechanisms of Striated Muscle Contraction Advances in Experimental Medicine and Biology 2007
Participants
Participant Of
Orthologous Events