Matter K, Dreyer F, Aktories K
Rudolf-Buchheim-Institut für Pharmakologie, Justus-Liebig-Universität, Giessen, F.R.G.
J Neurochem. 1989 Feb;52(2):370-6. doi: 10.1111/j.1471-4159.1989.tb09131.x.
Botulinum C2 toxin is known to ADP-ribosylate actin. The toxin effect was studied on [3H]noradrenaline secretion of PC12 cells. [3H]Noradrenaline release was stimulated five- to 15-fold by carbachol (100 microM) or K+ (50 mM) and 10-30-fold by the ionophore A23187 (5 microM). Pretreatment of PC12 cells with botulinum C2 toxin for 4-8 h at 20 degrees C, increased carbachol-, K+-, and A23187-induced, but not basal, [3H]noradrenaline release maximally 1.5-to three-fold, whereas approximately 75% of the cellular actin pool was ADP-ribosylated. Treatment of PC12 cells with botulinum C2 toxin for up to 1 h at 37 degrees C also increased stimulated [3H]noradrenaline secretion, whereas toxin treatment for greater than 1 h decreased the enhanced [3H]noradrenaline release stimulated by carbachol and K+ but not by A23187. Concomitantly with toxin-induced stimulation of secretion, 20-50% of the cellular actin was ADP-ribosylated, whereas greater than 60% of actin was modified when exocytosis was attenuated. The data indicate that ADP-ribosylation of actin by botulinum C2 toxin largely modulates stimulation of [3H]noradrenaline release. Moreover, the biphasic toxin effects suggest that distinct mechanisms are involved in the role of actin in secretion.
已知肉毒杆菌C2毒素可使肌动蛋白进行ADP核糖基化。研究了该毒素对PC12细胞[³H]去甲肾上腺素分泌的影响。卡巴胆碱（100微摩尔）或钾离子（50毫摩尔）可使[³H]去甲肾上腺素释放增加5至15倍，离子载体A23187（5微摩尔）可使其增加10至30倍。在20℃下用肉毒杆菌C2毒素预处理PC12细胞4至8小时，可使卡巴胆碱、钾离子和A23187诱导的（而非基础的）[³H]去甲肾上腺素释放最大增加1.5至3倍，而约75%的细胞肌动蛋白池被ADP核糖基化。在37℃下用肉毒杆菌C2毒素处理PC12细胞长达1小时也可增加刺激的[³H]去甲肾上腺素分泌，而毒素处理超过1小时则会降低卡巴胆碱和钾离子刺激的增强的[³H]去甲肾上腺素释放，但不会降低A23187刺激的释放。与毒素诱导的分泌刺激同时发生的是，20%至50%的细胞肌动蛋白被ADP核糖基化，而当胞吐作用减弱时，超过60%的肌动蛋白被修饰。数据表明，肉毒杆菌C2毒素对肌动蛋白的ADP核糖基化在很大程度上调节了[³H]去甲肾上腺素释放的刺激。此外，毒素的双相作用表明，肌动蛋白在分泌中的作用涉及不同的机制。
