Muscle-specific calpain, p94, interacts with the extreme C-terminal region of connectin, a unique region flanked by two immunoglobulin C2 motifs.
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.
Kinbara
K
K
Department of Molecular Biology, Institute of Molecular and Cellular Biosciences, University of Tokyo, Bunkyo-ku, Japan.
Sorimachi
H
H
Ishiura
S
S
Suzuki
K
K
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002154:Calpain / Q000737:chemistry / Q000378:metabolism*; D003001:Cloning, Molecular; D064211:Connectin; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism*; D015003:Yeasts / Q000235:genetics / Q000378:metabolism
D064211:Connectin; D018076:DNA, Complementary; D009124:Muscle Proteins; C577285:TTN protein, human; D011494:Protein Kinases; D002154:Calpain; C078134:calpain p94