Identification and localization of high molecular weight proteins in insect flight and leg muscle

EMBO J. 1990 Nov;9(11):3459-67. doi: 10.1002/j.1460-2075.1990.tb07554.x.


Thick and thin filaments in asynchronous flight muscle overlap nearly completely and thick filaments are attached to the Z-disc by connecting filaments. We have raised antibodies against a fraction of Lethocerus flight muscle myofibrils containing Z-discs and associated filaments and also against a low ionic strength extract of myofibrils. Monoclonal antibodies were obtained to proteins of 800 kd (p800), 700 kd (p700), 400 kd (p400) and alpha-actinin. The positions of the proteins in Lethocerus flight and leg myofibrils were determined by immunofluorescence and electron microscopy. p800 is in connecting filaments of flight myofibrils and in A-bands of leg myofibrils. p700 is in Z-discs of flight myofibrils and an immunologically related protein, p500, is in leg muscle Z-discs. p400 is in M-lines of both flight and leg myofibrils. Preliminary DNA sequencing shows that p800 is related to vertebrate titin and nematode twitchin. Molecules of p800 could extend from the Z-disc a short way along thick filaments, forming a mechanical link between the two structures. All three high molecular weight proteins probably stabilize the structure of the myofibril.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / immunology
  • Connectin
  • Extremities
  • Flight, Animal
  • Fluorescent Antibody Technique
  • Immunohistochemistry
  • Insecta / anatomy & histology
  • Insecta / ultrastructure*
  • Molecular Sequence Data
  • Molecular Weight
  • Muscle Proteins / chemistry
  • Muscle Proteins / immunology*
  • Muscle Proteins / metabolism
  • Muscles / ultrastructure*
  • Protein Kinases*


  • Antibodies, Monoclonal
  • Connectin
  • Muscle Proteins
  • Protein Kinases