Li G, Regazzi R, Balch W E, Wollheim C B
Département de Médecine, Centre Médical Universitaire, Geneva, Switzerland.
FEBS Lett. 1993 Jul 26;327(2):145-9. doi: 10.1016/0014-5793(93)80159-r.
A synthetic peptide (rab3AL) corresponding to the effector domain of rab3, a small GTP-binding protein, stimulated basal and potentiated Ca(2+)- as well as GTP gamma S-evoked insulin secretion about 2-fold from streptolysin-O permeabilized HIT cells. This effect was specific, since the analogous peptides of ras or rab1 did not affect the exocytotic event. The more than additive effect of rab3AL on Ca2+ or GTP gamma S stimulation indicates a distinct mode of action of the peptide. The partial loss of cytosolic proteins from permeabilized cells was accompanied by a faster run-down of the secretory response to Ca2+ than the one to GTP gamma S. The persistent effect of rab3AL under these conditions points to a membrane localization of its target. These results suggest that rab3 and its effector are involved in the regulation of insulin secretion.
一种与小GTP结合蛋白rab3的效应结构域相对应的合成肽（rab3AL），可刺激基础胰岛素分泌，并使经链球菌溶血素-O通透处理的HIT细胞的Ca(2+)以及GTPγS诱发的胰岛素分泌增强约2倍。这种效应具有特异性，因为ras或rab1的类似肽并不影响胞吐事件。rab3AL对Ca2+或GTPγS刺激的超加性效应表明该肽具有独特的作用方式。通透细胞中胞质蛋白的部分丢失伴随着对Ca2+的分泌反应比GTPγS更快地减弱。在这些条件下rab3AL的持续作用表明其靶点定位于细胞膜。这些结果提示rab3及其效应物参与胰岛素分泌的调节。
