A variably spliced region in the type 1 ryanodine receptor may participate in an inter-domain interaction
| Autor: | Robert T. Dirksen, Nicole A. Beard, Takashi Kimura, Lan Wei, Angela F. Dulhunty, Suzy M. Pace |
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| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: |
Gene isoform
medicine.medical_specialty Molecular Sequence Data Peptide Biology Transfection Biochemistry law.invention law Internal medicine mental disorders medicine Animals Amino Acid Sequence Threonine Muscle Skeletal Molecular Biology Peptide sequence RYR1 chemistry.chemical_classification Sequence Homology Amino Acid Ryanodine receptor Binding protein Genetic Variation Ryanodine Receptor Calcium Release Channel Cell Biology Exons musculoskeletal system humanities Recombinant Proteins Alternative Splicing Kinetics Endocrinology chemistry Recombinant DNA Rabbits tissues Sequence Alignment Research Article |
| Popis: | The aim of the present study was to examine residues that are variably spliced in the juvenile and adult isoforms of the skeletal-muscle RyR1 (type 1 ryanodine receptor). The juvenile ASI(−) splice variant is less active than the adult ASI(+) variant and is overexpressed in patients with DM (myotonic dystrophy) [Kimura, Nakamori, Lueck, Pouliquin, Aoike, Fujimura, Dirksen, Takahashi, Dulhunty and Sakoda (2005) Hum. Mol. Genet. 14, 2189–2200]. In the present study, we explore the ASI region using synthetic peptides corresponding to rabbit RyR1 residues Thr3471-Gly3500 either containing [PASI(+)] or lacking [PASI(−)] the ASI residues. Both peptides increased [3H]ryanodine binding to rabbit RyR1s, increased Ca2+ release from sarcoplasmic reti-culum vesicles and increased single RyR1 channel activity. The peptide PASI(−) was more active in each case than PASI(+). [3H]Ryanodine binding to recombinant ASI(+)RyR1 or ASI(−)-RyR1 was enhanced more by PASI(−) than PASI(+), with the greatest increase seen when PASI(−) was added to ASI(−)RyR1. The activation of the RyR channels is consistent with the hypo-thesis that the peptides interrupt an inhibitory inter-domain inter-action and that PASI(−) is more effective at interrupting this interaction than PASI(+). We therefore suggest that the ASI(−) sequence interacts more tightly than the ASI(+) sequence with its binding partner, so that the ASI(−)RyR1 is more strongly inhibited (less active) than the ASI(+)RyR1. Thus the affinity of the binding partners in this inter-domain interaction may deter-mine the activities of the mature and juvenile isoforms of RyR1 and the stronger inhibition in the juvenile isoform may contribute to the myopathy in DM. |
| Databáze: | OpenAIRE |
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