Identification of 30 kDa calsequestrin-binding protein, which regulates calcium release from sarcoplasmic reticulum of rabbit skeletal muscle.
In a previous study [Yamaguchi, Kawasaki and Kasai (1995) Biochem. Biophys. Res. Commun. 210, 648-653], we showed that the stilbene derivative 4,4'-di-isothiocyanostilbene-2,2'-disulphonic acid activates the Ca2+ channel in the sarcoplasmic reticulum (SR) in rabbit skeletal muscle, and it does not bind to the channel protein itself but to the SR 30 kDa protein. Furthermore, the 30 kDa protein was shown to bind to calsequestrin (CSQ), which is one of the regulators of the Ca2+ release channel in the SR. In the present study, we determined the partial amino acid sequence of the CSQ-binding 30 kDa protein and, consequently, this protein was proved to be highly similar to ADP/ATP translocase (AAT) expressed in the mitochondria in a variety of cells. By Western-blotting analysis, the CSQ-binding 30 kDa protein was recognized by the antibody raised against bovine cardiac AAT and, furthermore, depolarization-induced Ca2+ release monitored in the rabbit skeletal muscle triads was significantly activated by the antibody. As a result of cloning and sequencing of the cDNA encoding AAT of the rabbit skeletal muscle, the amino acid sequence was found to be the same as that of the CSQ-binding 30 kDa protein determined above. Furthermore, the expressed product of the cDNA encoding AAT in Escherichia coli was proved to bind to CSQ. These results suggest that AAT itself is expressed in the rabbit skeletal muscle SR and regulates the Ca2+ release from the SR; that is, excitation-contraction coupling of the skeletal muscle cell.
Yamaguchi
N
N
Division of Biophysical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan. n-yama@bpe.es.osaka-u.ac.jp
Kasai
M
M
D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D002417:Cattle; D003001:Cloning, Molecular; D004926:Escherichia coli; D006706:Homeostasis; D008565:Membrane Proteins; D008928:Mitochondria / Q000201:enzymology; D008929:Mitochondria, Heart / Q000201:enzymology; D000226:Mitochondrial ADP, ATP Translocases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006899:Mixed Function Oxygenases; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009124:Muscle Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D011994:Recombinant Proteins; D000226:Mitochondrial ADP, ATP Translocases; C498842:Junctin protein, Oryctolagus cuniculus; D006899:Mixed Function Oxygenases; D002118:Calcium