A negatively charged region of the skeletal muscle ryanodine receptor is involved in Ca(2+)-dependent regulation of the Ca(2+) release channel.
The ryanodine receptor/Ca(2+) release channels from skeletal (RyR1) and cardiac (RyR2) muscle cells exhibit different inactivation profiles by cytosolic Ca(2+). D3 is one of the divergent regions between RyR1 (amino acids (aa) 1872-1923) and RyR2 (aa 1852-1890) and may contain putative binding site(s) for Ca(2+)-dependent inactivation of RyR. To test this possibility, we have deleted the D3 region from RyR1 (DeltaD3-RyR1), residues 1038-3355 from RyR2 (Delta(1038-3355)-RyR2) and inserted the skeletal D3 into Delta(1038-3355)-RyR2 to generate sD3-RyR2. The channels formed by DeltaD3-RyR1 and Delta(1038-3355)-RyR2 are resistant to inactivation by mM [Ca(2+)], whereas the chimeric sD3-RyR2 channel exhibits significant inactivation at mM [Ca(2+)]. The DeltaD3-RyR1 channel retains its sensitivity to activation by caffeine, but is resistant to inactivation by Mg(2+). The data suggest that the skeletal D3 region is involved in the Ca(2+)-dependent regulation of the RyR1 channel.
Hayek
S M
SM
Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
Zhao
J
J
Bhat
M
M
Xu
X
X
Nagaraj
R
R
Pan
Z
Z
Takeshima
H
H
Ma
J
J
D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000502:physiology*; D006224:Cricetinae; D003412:Cricetulus; D017136:Ion Transport; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D018482:Muscle, Skeletal / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D016415:Sequence Alignment; D017384:Sequence Deletion; D014162:Transfection
D009124:Muscle Proteins; D011993:Recombinant Fusion Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D002118:Calcium