N-ethylmaleimide-sensitive factor acts at a profusion ATP-dependent step in Ca2+-activated exocytosis
N-ethylmaleimide-sensitive factor acts at a profusion ATP-dependent step in Ca2+-activated exocytosis
复制标题
DOI：
10.1074/jbc.271.34.20223
复制
发表时间：
1996-08-23
影响因子：
4.8
通讯作者：
Martin, TFJ
中科院分区：
文献类型：
--
作者：
Banerjee, A;Barry, VA;Martin, TFJ
NSF（N-乙基马来酰亚胺敏感因子）的ATP依赖性活性重排可溶性NSF附着蛋白（SNAP）受体（SNARE）蛋白复合物被认为是膜融合的驱动力。在渗透性PC 12细胞中，分泌囊泡与质膜的Ca 2+激活融合需要ATP;然而，ATP的需求是在Ca 2+触发的融合反应之前的引发步骤。虽然磷酸肌醇磷酸化是引发所需的关键反应，但也需要额外的ATP依赖性反应。在这里，我们报告，NSF催化的SNARE蛋白复合物的重排发生在ATP依赖性引发，NSF与α-SNAP（可溶性NSF附着蛋白）所需的ATP依赖性引发，而不是Ca 2+触发的融合，表明NSF的行为在ATP依赖性的融合前步骤，而不是在融合本身。NSF催化的SNARE蛋白的活化可以重组膜以产生囊泡-质膜预融合中间体，其准备通过Ca 2+依赖性机制转化为完全融合。
An ATP-dependent activity of NSF (N-ethylmaleimide-sensitive factor) that rearranges soluble NSF attachment protein (SNAP) receptor (SNARE) protein complexes was proposed to be the driving force for membrane fusion. The Ca2+-activated fusion of secretory vesicles with the plasma membrane in permeable PC12 cells requires ATP; however, the ATP requirement is for a priming step that precedes the Ca2+-triggered fusion reaction. While phosphoinositide phosphorylation is a key reaction required for priming, additional ATP-dependent reactions are also necessary. Here we report that the NSF-catalyzed rearrangement of SNARE protein complexes occurs during ATP-dependent priming, NSF with alpha-SNAP (soluble NSF attachment protein) were required for ATP-dependent priming but not Ca2+-triggered fusion, indicating that NSF acts at an ATP-dependent prefusion step rather than at fusion itself. NSF-catalyzed activation of SNARE proteins may reorganize membranes to generate a vesicle-plasma membrane prefusion intermediate that is poised for conversion to full fusion by Ca2+-dependent mechanisms.