Fruen B R, Mickelson J R, Shomer N H, Velez P, Louis C F
Department of Veterinary PathoBiology, University of Minnesota, St. Paul 55108.
FEBS Lett. 1994 Sep 26;352(2):123-6. doi: 10.1016/0014-5793(94)00931-7.
The cardiac muscle isoform of the ryanodine receptor/Ca2+ release channel (RYR) has been proposed to be an important target of cyclic ADP-ribose (cADPR) action in mammalian cells. However, we now demonstrate that neither cADPR (0.1-5 microM), nor the related metabolites beta-NAD+ (0.1-30 mM) and ADP-ribose (0.1-5 microM), affected cardiac RYR activity as determined by [3H]ryanodine binding to cardiac sarcoplasmic reticulum (SR) vesicles. Similarly, cADPR (1 microM) failed to activate single cardiac RYR channels in planar lipid bilayers. Skeletal muscle SR [3H]ryanodine binding was also unaffected by cADPR (up to 30 microM). These results argue against a direct role for the well-characterized RYRs of cardiac or skeletal muscle in mediating cADPR-activated Ca2+ release.
有人提出，雷诺丁受体/钙离子释放通道（RYR）的心肌亚型是环二磷酸腺苷核糖（cADPR）在哺乳动物细胞中发挥作用的重要靶点。然而，我们现在证明，无论是cADPR（0.1 - 5微摩尔），还是相关代谢产物β - 烟酰胺腺嘌呤二核苷酸（β - NAD +，0.1 - 30毫摩尔）和二磷酸腺苷核糖（ADP - 核糖，0.1 - 5微摩尔），均不会影响通过[³H]雷诺丁与心肌肌浆网（SR）囊泡结合所测定的心肌RYR活性。同样，cADPR（1微摩尔）未能激活平面脂质双分子层中的单个心肌RYR通道。cADPR（高达30微摩尔）也不影响骨骼肌SR的[³H]雷诺丁结合。这些结果表明，心肌或骨骼肌中已明确的RYR在介导cADPR激活的钙离子释放过程中并无直接作用。
