Muscle-specific calpain, p94, interacts with the extreme C-terminal region of connectin, a unique region flanked by two immunoglobulin C2 motifs

Arch Biochem Biophys. 1997 Jun 1;342(1):99-107. doi: 10.1006/abbi.1997.0108.


Using the yeast two-hybrid system, we have recently reported that skeletal muscle-specific calpain, p94, binds specifically to connectin (or titin), a gigantic muscle elastic protein. Connectin has at least two binding sites for p94; one is at the N2-line region and the other is at the extreme C-terminus. In order to analyze the interaction between p94 and the C-terminus of connectin, we examined the C-terminal sequence of human skeletal muscle connectin. The sequence was essentially identical to that of heart muscle reported by Labeit and Kolmerer (1995, Science 270, 293-296), and the minimal binding site for p94 contained two IgC2 motifs and the intervening sequence called "M-is7." The exon encoding M-is7 is reported to be alternatively spliced depending on muscle tissues, resulting in the existence of both types of connectin with and without M-is7. However, the C-terminal region of connectin bound to p94 through M-is7. Our results suggest that the interaction between p94 and the C-terminus of skeletal muscle-type connectin is involved in tissue-specific myofibriogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Binding Sites
  • Calpain / chemistry
  • Calpain / metabolism*
  • Cloning, Molecular
  • Connectin
  • DNA, Complementary / genetics
  • Humans
  • Molecular Sequence Data
  • Muscle Proteins / chemistry
  • Muscle Proteins / metabolism*
  • Muscle, Skeletal / metabolism*
  • Protein Kinases / chemistry
  • Protein Kinases / metabolism*
  • Yeasts / genetics
  • Yeasts / metabolism


  • Connectin
  • DNA, Complementary
  • Muscle Proteins
  • TTN protein, human
  • Protein Kinases
  • Calpain
  • calpain p94