Brady S T
Nature. 1985;317(6032):73-5. doi: 10.1038/317073a0.
Identification of the ATPase involved in fast axonal transport of membranous organelles has proven difficult. Myosin and dynein, other ATPases known to be involved in cell motility, have properties that are inconsistent with the established properties of fast axonal transport, an essential component of which is readily solubilized in physiological buffer conditions rather than being stably associated with either membranous organelles or cytoskeletal elements. Adenylyl imidodiphosphate (AMP-PNP), a nonhydrolysable analogue of ATP, is a potent inhibitor of fast axonal transport that results in a stable interaction of membranous organelles with microtubules. Here we report the identification and partial characterization of an ATPase activity from brain whose binding to microtubules is stabilized by AMP-PNP. This ATPase activity seems to be associated with a polypeptide of relative molecular mass (Mr) 130,000 that is highly enriched in microtubule pellets after incubation with AMP-PNP and a soluble fraction from chick brain. This novel ATPase fraction has the predicted characteristics of the motor involved in fast axonal transport. Common features between the ATPase and fast axonal transport include interaction with the cytoskeleton in the presence of AMP-PNP, ready extractability, no Ca2+ dependence and inhibition by EDTA.
事实证明，要鉴定参与膜性细胞器快速轴突运输的ATP酶很困难。肌球蛋白和动力蛋白是已知的参与细胞运动的其他ATP酶，它们的特性与快速轴突运输的既定特性不一致，快速轴突运输的一个重要组成部分很容易在生理缓冲条件下溶解，而不是与膜性细胞器或细胞骨架成分稳定结合。腺苷亚氨基二磷酸（AMP-PNP）是一种不可水解的ATP类似物，是快速轴突运输的有效抑制剂，它会导致膜性细胞器与微管稳定相互作用。在此，我们报告了从大脑中鉴定出的一种ATP酶活性及其部分特性，该酶与微管的结合可被AMP-PNP稳定。这种ATP酶活性似乎与一种相对分子质量（Mr）为130,000的多肽相关，在用AMP-PNP和鸡脑可溶性组分孵育后，该多肽在微管沉淀中高度富集。这种新的ATP酶组分具有参与快速轴突运输的动力蛋白的预测特征。该ATP酶与快速轴突运输之间的共同特征包括在AMP-PNP存在下与细胞骨架的相互作用、易于提取、不依赖Ca2+以及被EDTA抑制。
