Structural Basis for Calcium-Regulated Relaxation of Striated Muscles at Interaction Sites of Troponin with Actin and Tropomyosin

  • Kenji Murakami
  • Fumiaki Yumoto
  • Shin-ya Ohki
  • Takuo Yasunaga
  • Masaru Tanokura
  • Takeyuki Wakabayashi
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 592)


Muscle contraction, in general, is regulated by the intracellular calcium-ion concentration. Ca2+-regulation in skeletal or cardiac muscle of vertebrate is mediated at the level of thin filaments consisting of actin, tropomyosin, and troponin. However, pure actin filaments themselves activate contraction irrespective of calcium concentration. Troponin,1 together with tropomyosin, is required to regulate contraction.2 Troponin consists of three subunits:3 inhibitory TnI, Ca2+-binding TnC, and tropomyosin-binding TnT. Troponin has an elongated shape and forms two structural regions, which are a long tail region containing the N-terminal region of TnT (TnT1 (chicken skeletal residues 1–164 of TnT)4) and a globular head region containing TnI, TnC, and the C-terminal region of TnT [TnT2 (chicken skeletal residues 165–263 of TnT)]. The globular head region plays a central role in regulating muscle contraction.5


Ternary Complex Core Domain Myosin Head Inhibitory Region Switch Region 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer 2007

Authors and Affiliations

  • Kenji Murakami
    • 1
  • Fumiaki Yumoto
    • 2
  • Shin-ya Ohki
    • 3
  • Takuo Yasunaga
    • 4
  • Masaru Tanokura
    • 2
  • Takeyuki Wakabayashi
    • 1
  1. 1.Department of Biosciences, School of Science and EngineeringTeikyo UniversityUtsunomiya
  2. 2.Department of Applied Biological Chemistry, Graduate School of Agricultural and Life SciencesUniversity of TokyoTokyo
  3. 3.Japan Advanced Institute of Science and Technology (JAIST)Ishikawa
  4. 4.Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems EngineeringKyushu Institute of TechnologyFukuokaJapan

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