Possible contribution of titin filaments to the compliant series elastic component in horseshoe crab skeletal muscle fibers

Adv Exp Med Biol. 2000;481:371-80; discussion 381-2. doi: 10.1007/978-1-4615-4267-4_22.


In horseshoe crab skeletal muscle fibers, the extension of SEC at the maximum isometric force P0 is about 6% of the slack fiber length L0 (sarcomere length, 7 microns), i.e., about 210 nm per half-sarcomere, being too large to be explained by the cross-bridge and the thin filament elasticities. Cinematographic studies of isometrically contracting myofibril bundes indicate that the highly compliant SEC mostly originates from the "elastic" thick filament misalignment in each A-band during isometric force generation. Possible contribution of the titin filaments to the "elastic" thick filament misalignment is discussed.

MeSH terms

  • Animals
  • Calcium / physiology
  • Connectin
  • Elasticity
  • Horseshoe Crabs
  • In Vitro Techniques
  • Isometric Contraction / physiology*
  • Muscle Fibers, Skeletal / physiology*
  • Muscle Proteins / physiology*
  • Muscle, Skeletal / physiology*
  • Myofibrils / physiology*
  • Myosins / physiology
  • Protein Kinases / physiology*
  • Sarcomeres / physiology


  • Connectin
  • Muscle Proteins
  • Protein Kinases
  • Myosins
  • Calcium