Quinn K E, Castellani L, Ondrias K, Ehrlich B E
Department of Physiology, University of Connecticut, Farmington 06030, USA.
Am J Physiol. 1998 Feb;274(2):R494-502. doi: 10.1152/ajpregu.1998.274.2.R494.
Electron-microscopic analysis was used to show that invertebrate muscle has feetlike structures on the sarcoplasmic reticulum (SR) displaying the typical four-subunit appearance of the calcium (Ca2+) release channel/ryanodine receptor (RyR) observed in vertebrate skeletal muscle (K. E. Loesser, L. Castellani, and C. Franzini-Armstrong. J. Muscle Res. Cell Motil. 13: 161-173, 1992). SR vesicles from invertebrate muscle exhibited specific ryanodine binding and single channel currents that were activated by Ca2+, caffeine, and ATP and inhibited by ruthenium red. The single channel conductance of this invertebrate RyR was lower than that of the vertebrate RyR (49 and 102 pS, respectively). Activation of lobster and scallop SR Ca2+ release channel, in response to cytoplasmic Ca2+ (1 nM-10 mM), reflected a bell-shaped curve, as is found with the mammalian RyR. In contrast to a previous report (J.-H. Seok, L. Xu, N. R. Kramarcy, R. Sealock, and G. Meissner, J. Biol. Chem. 267: 15893-15901, 1992), our results show that regulation of the invertebrate and vertebrate RyRs is quite similar and suggest remarkably similar paths in these diverse organisms.
电子显微镜分析表明，无脊椎动物肌肉的肌浆网（SR）上有类似足状的结构，呈现出在脊椎动物骨骼肌中观察到的典型的钙（Ca2+）释放通道/雷诺丁受体（RyR）的四亚基外观（K. E. 洛瑟、L. 卡斯特拉尼和C. 弗兰齐尼 - 阿姆斯特朗。《肌肉研究与细胞运动》杂志。13: 161 - 173, 1992）。无脊椎动物肌肉的SR囊泡表现出特异性的雷诺丁结合以及单通道电流，该电流可被Ca2+、咖啡因和ATP激活，并被钌红抑制。这种无脊椎动物RyR的单通道电导低于脊椎动物的RyR（分别为49和102 pS）。龙虾和扇贝SR Ca2+释放通道对细胞质Ca2+（1 nM - 10 mM）的激活反映出一条钟形曲线，这与哺乳动物RyR的情况相同。与之前的一份报告（J.-H. 石、L. 徐、N. R. 克拉马尔西、R. 西洛克和G. 迈斯纳，《生物化学杂志》。267: 15893 - 15901, 1992）不同，我们的结果表明无脊椎动物和脊椎动物RyR的调节非常相似，并暗示在这些不同的生物体中有非常相似的途径。
