Amino acids 1-1,680 of ryanodine receptor type 1 hold critical determinants of skeletal type for excitation-contraction coupling. Role of divergence domain D2.
To identify domains of the ryanodine receptor (RyR1) that are functionally relevant for excitation-contraction (EC) coupling in vivo, we have studied the ability of RyR1/RyR3 chimera to rescue skeletal EC coupling in dyspedic myotubes. In this work we show that chimeric receptors containing amino acids 1-1,680 of RyR1 were able to render depolarization-induced Ca2+ release to RyR3. Within this region, residues 1,272-1,455, containing divergent domain D2 of RyR1, proved to be a critical element because the absence of this region selectively abolished depolarization-evoked Ca2+ transients without affecting chemically induced activation. Although the D2 domain by itself failed to restore skeletal EC coupling to RyR3, the addition of the D2 region resulted in a dramatic enhancement of EC coupling restored by an RyR3 chimera containing amino acids 1,681-3,770 of RyR1. These results suggest that although the D2 domain of RyR1 plays a key role during EC coupling, additional region(s) from the N-terminal end of RyR1 as well as previously identified regions of the central portion of the receptor are needed in order to allow normal EC coupling.
Perez
Claudio F
CF
Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. cperez@zeus.bwh.harvard.edu
Mukherjee
Santwana
S
Allen
Paul D
PD
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D066298:In Vitro Techniques; D007700:Kinetics; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D019837:Ryanodine Receptor Calcium Release Channel / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D011993:Recombinant Fusion Proteins; D019837:Ryanodine Receptor Calcium Release Channel