Schroeder P, Just I, Aktories K
Institut für Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg-Saar/Germany.
Eur J Cell Biol. 1994 Feb;63(1):3-9.
Adenine nucleotides were shown to increase the ADP-ribosylation of actin by Clostridium perfringens iota and Clostridium botulinum C2 toxin in membranes from human platelets, hamster fat cells, rat liver- and rat brain cells. ATP and ATP gamma S were the most effective agents with ATP showing half-maximal and maximal effects at about 2 and 10 microM, respectively. The rank order of various adenine nucleotides were ATP = ATP gamma S > ADP > AMP-PNP >> AMP = cAMP. Guanine nucleotides showed the same rank order of potencies but were less effective than adenine nucleotides. Adenine nucleotides which increased ADP-ribosylation were able to release actin from membranes. [32P]ADP-ribosylated rabbit skeletal muscle actin, which is unable to polymerize, was used as tool to study membrane-binding of actin. The [32P]ADP-ribosylated actin bound to stripped rat liver membranes in a saturable, time- and temperature-dependent manner. ATP inhibited the binding of ADP-ribosylated actin with a half-maximal and maximal inhibitory concentration at about 50 and 300 microM, respectively. The data indicate that actin-binding to membranes is prevented or reversed in the presence of adenine nucleotides thereby increasing the accessibility of actin for ADP-ribosylation by toxins.
在人血小板、仓鼠脂肪细胞、大鼠肝细胞和大鼠脑细胞的膜中，已表明腺嘌呤核苷酸可增加产气荚膜梭菌iota毒素和肉毒梭菌C2毒素对肌动蛋白的ADP-核糖基化作用。ATP和ATPγS是最有效的试剂，ATP分别在约2 microM和10 microM时显示出半最大效应和最大效应。各种腺嘌呤核苷酸的效力排序为ATP = ATPγS > ADP > AMP-PNP >> AMP = cAMP。鸟嘌呤核苷酸显示出相同的效力排序，但比腺嘌呤核苷酸效果差。增加ADP-核糖基化的腺嘌呤核苷酸能够从膜中释放肌动蛋白。[32P]ADP-核糖基化的兔骨骼肌肌动蛋白无法聚合，被用作研究肌动蛋白与膜结合的工具。[32P]ADP-核糖基化的肌动蛋白以饱和、时间和温度依赖性方式与去除蛋白的大鼠肝细胞膜结合。ATP抑制ADP-核糖基化肌动蛋白的结合，半最大抑制浓度和最大抑制浓度分别约为50 microM和300 microM。数据表明，在腺嘌呤核苷酸存在下，肌动蛋白与膜的结合被阻止或逆转，从而增加了肌动蛋白被毒素进行ADP-核糖基化的可及性。
