A variably spliced region in the type 1 ryanodine receptor may participate in an inter-domain interaction
A variably spliced region in the type 1 ryanodine receptor may participate in an inter-domain interaction
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DOI：
10.1042/bj20060686
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发表时间：
2007-01-01
影响因子：
4.1
通讯作者：
Dulhunty, Angela F.
中科院分区：
文献类型：
--
作者：
Kimura, Takashi;Pace, Suzy M.;Dulhunty, Angela F.
本研究的目的是检查的残基，在青少年和成人同种型的骨骼肌RyR 1（1型ryanodine受体）的拼接。青少年ASI（-）剪接变体的活性低于成人ASI（+）变体，并且在DM（强直性肌营养不良）患者中过表达[Kimura，Nakamori，Lueck，Pouliquin，Aoike，Fujimura，Dirksen，Takahashi，Dulhunty and Sakoda（2005）]。摩尔Genet. 14，2189-2200]。在本研究中，我们使用与兔RyR 1残基Thr（3471）-Gly（3500）相对应的合成肽（含有[PASI（4-）]或缺乏[PASI（-）] ASI残基）来探索ASI区域。这两种肽增加[H-3]ryanodine结合兔RyR 1 s，增加Ca 2+释放肌浆网囊泡和增加单RyR 1通道活性。肽PASI（-）在每种情况下比PASI（+）更有活性。PASI（-）比PASI（+）更能增强[3 H]Ryanodine与重组AS 1（+）RyR 1或ASI（-）-RyR 1的结合，当PASI（-）加入ASI（-）RyR 1时，观察到最大的增加。RyR通道的激活与肽中断抑制性结构域间相互作用以及PASI（-）比PASI（+）更有效地中断这种相互作用的假设一致。因此，我们认为ASI（-）序列与其结合伴侣的相互作用比ASI（+）序列更紧密，因此ASI（-）RyR 1比ASI（+）RyR 1受到更强的抑制（活性更低）。因此，在这种结构域间相互作用的结合伙伴的亲和力可能决定的活动的成熟和青少年亚型的RyR 1和青少年亚型的较强的抑制可能有助于在DM的肌病。
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 Thr(3471)-Gly(3500) either containing [PASI(4-)] or lacking [PASI(-)] the ASI residues. Both peptides increased [H-3]ryanodine binding to rabbit RyR1s, increased Ca2+ release from sarcoplasmic reticulum vesicles and increased single RyR1 channel activity. The peptide PASI(-) was more active in each case than PASI(+). [3 H]Ryanodine binding to recombinant AS1(+)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 hypothesis that the peptides interrupt an inhibitory inter-domain interaction 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 determine 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.