EXOCYTOTIC FUSION IS ACTIVATED BY RAB3A PEPTIDES
EXOCYTOTIC FUSION IS ACTIVATED BY RAB3A PEPTIDES
复制标题
DOI：
10.1038/360270a0
复制
发表时间：
1992-11-19
期刊：
影响因子：
64.8
通讯作者：
FERNANDEZ, JM
中科院分区：
文献类型：
--
作者：
OBERHAUSER, AF;MONCK, JR;FERNANDEZ, JM
对酵母和哺乳动物系统中细胞内运输的研究表明，小 GTP 结合蛋白 Rab 家族的成员是膜融合的调节剂1-10。我们使用膜片钳技术直接测量胞吐融合事件，并研究 GTP 结合蛋白在调节肥大细胞胞吐作用中的作用。在没有其他细胞内信使的情况下，肥大细胞的细胞内灌注 GTP-gammaS 足以触发完全的胞吐脱颗粒11。在这里，我们证明 GTP 是 GTP-gammaS 诱导的脱颗粒的有效抑制剂，表明 GTP 结合蛋白的持续激活足以进行膜融合。我们发现，与 Rab3a12 效应结构域的一部分相对应的合成寡肽可刺激完全胞吐脱粒，类似于 GTP-gammaS 诱导的脱颗粒。该反应对 Rab3a 序列具有选择性，并且严格依赖于 Mg2+ 和 ATP。这表明 Rab3 蛋白的持续激活会导致胞吐融合。 GDP-betaS 可以加速肽反应，表明 Rab3a 肽与内源性 Rab3 蛋白竞争靶效应蛋白上的结合位点，从而在激活时引起融合。
STUDIES of intracellular traffic in yeast and mammalian systems have implicated members of the Rab family of small GTP-binding proteins as regulators of membrane fusion1-10. We have used the patch clamp technique to measure exocytotic fusion events directly and investigate the role of GTP-binding proteins in regulating exocytosis in mast cells. Intracellular perfusion of mast cells with GTP-gammaS is sufficient to trigger complete exocytotic degranulation in the absence of other intracellular messengers11. Here we show that GTP is a potent inhibitor of GTP-gammaS-induced degranulation, indicating that sustained activation of a GTP-binding protein is sufficient for membrane fusion. We have found that synthetic oligopeptides, corresponding to part of the effector domain of Rab3a12, stimulate complete exocytotic degranulation, similar to that induced by GTP-gammaS. The response is selective for Rab3a sequence and is strictly dependent on Mg2+ and ATP. This suggests that sustained activation of a Rab3 protein causes exocytotic fusion. The peptide response can be accelerated by GDP-betaS, suggesting that Rab3a peptides compete with endogenous Rab3 proteins for a binding site on a target effector protein, which causes fusion on activation.