The heterotrimeric GTP-binding protein, GS, modulates the Cl- conductance of rat parotid acinar secretory granules.
The heterotrimeric GTP-binding protein, GS, modulates the Cl- conductance of rat parotid acinar secretory granules.
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异三聚体 GTP 结合蛋白 GS 调节大鼠腮腺腺泡分泌颗粒的 Cl-电导。
DOI：
10.1006/bbrc.1997.7354
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Dijulio,DH
中科院分区：
文献类型：
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作者：
Watson,EL;Izutsu,KT;Jacobson,KL;Dijulio,DH
已有报道称GSα存在于大鼠腮腺腺泡分泌颗粒膜组分中。在本研究中，我们通过测量颗粒裂解来评估Gsα在分泌颗粒(SG)上的表位取向以及GST调节分离颗粒的CL−电导的能力。GSα与SGM的细胞质表面相关。氟化铝(AlF_4−、20μM Al~(3+)和10 mM F-−)显著促进颗粒溶解，这种作用可被β拮抗剂阻断。霍乱毒素(5μg/ml)与AlF_4−的作用相似，而百日咳毒素(0.5μg/ml)对颗粒溶解无明显影响。而GTPγS则以浓度依赖的方式抑制颗粒溶解。Gsα在SGm上的定位，以及AlF4−和霍乱毒素对颗粒溶解的影响，支持了Gs在胞吐过程中的作用。
Gsαhas been reported to be present in rat parotid acinar secretory granule membrane (SGM) fractions. In the present study, we evaluated epitope orientation of Gsαon the secretory granule (SG) and the ability of Gsto modulate the Cl−conductance of isolated granules by measuring granule lysis. Gsαwas found to be associated with the cytoplasmic face of the SGM. Aluminum fluroide (AlF4−, 20μM Al3+and 10 mM F−) significantly increased granule lysis and this effect was blocked by GDPβS. Cholera toxin (5μg/ml) mimicked the effects of AlF4−on granule lysis, whereas pertussis toxin (0.5μg/ml) was without effect. GTPγS, however, reduced granule lysis in a concentration-dependent manner. The orientation of Gsαon the SGM as well as the effects of AlF4−and cholera toxin on granule lysis lends support for a role of Gsin the exocytotic process.