Creutz C E, Sterner D C
Biochem Biophys Res Commun. 1983 Jul 18;114(1):355-64. doi: 10.1016/0006-291x(83)91635-2.
The calcium dependence of the binding of synexin to isolated chromaffin granules has been investigated. The calcium dependence was found to be pH sensitive, binding occurring at higher Ca2+ concentrations at lower values of pH. At pH 7.2 half-maximal binding occurred at 4 microM Ca2+. This is a lower Ca2+ concentration than the 200 microM that is required to give half-maximal self-association of synexin or membrane aggregation by synexin. The data therefore suggest that in the chromaffin cell stimulated to release catecholamines and proteins by exocytosis synexin first binds to membranes and then associates with itself to draw membranes together in preparation for fusion.
已对联会蛋白与分离的嗜铬粒蛋白结合的钙依赖性进行了研究。发现钙依赖性对pH敏感，在较低pH值时，较高的Ca2+浓度下会发生结合。在pH 7.2时，半数最大结合发生在4微摩尔Ca2+浓度下。此Ca2+浓度低于使联会蛋白半数最大自缔合或由联会蛋白引起膜聚集所需的200微摩尔。因此，数据表明，在通过胞吐作用被刺激释放儿茶酚胺和蛋白质的嗜铬细胞中，联会蛋白首先与膜结合，然后自身缔合以将膜拉拢在一起，为融合做准备。
