Prasad K, Barouch W, Greene L, Eisenberg E
Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892.
J Biol Chem. 1993 Nov 15;268(32):23758-61.
Immediately after clathrin-coated pits pinch off from the cell membrane to form clathrin-coated vesicles, clathrin dissociates from the vesicles. In vitro studies suggest that this dissociation is carried out by the uncoating ATPase, a constitutive member of the 70-kDa heat shock family. Aside from the requirement for ATP, nothing is known about the regulation of the uncoating process. We now show that clathrin baskets prepared from highly purified clathrin and AP2, the assembly protein associated with plasma membrane coated vesicles, cannot be uncoated by the bovine brain uncoating ATPase alone. A 100-kDa protein cofactor, which was isolated from coated vesicles, is essential for uncoating by the uncoating ATPase. This cofactor restores normal uncoating when present at a molar ratio of about 1 to 10 to clathrin and uncoating ATPase.
网格蛋白包被小窝从细胞膜上脱离形成网格蛋白包被小泡后，网格蛋白立即从小泡上解离。体外研究表明，这种解离是由去包被ATP酶完成的，它是70 kDa热休克家族的一个组成成员。除了对ATP的需求外，对于去包被过程的调节一无所知。我们现在发现，由高度纯化的网格蛋白和AP2（与质膜包被小泡相关的组装蛋白）制备的网格蛋白篮，不能仅由牛脑去包被ATP酶去包被。从包被小泡中分离出的一种100 kDa的蛋白质辅因子，对于去包被ATP酶的去包被作用至关重要。当该辅因子与网格蛋白和去包被ATP酶以大约1比10的摩尔比存在时，可恢复正常的去包被过程。
