Reversible condensation of mast cell secretory products in vitro.
Reversible condensation of mast cell secretory products in vitro.
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肥大细胞分泌产物在体外的可逆浓缩。
DOI：
10.1016/s0006-3495(91)82317-7
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发表时间：
1991
影响因子：
3.4
通讯作者：
Verdugo,P
中科院分区：
文献类型：
--
作者：
Fernandez,JM;Villalon,M;Verdugo,P
我们研究了肥大细胞分泌中分泌产物缩合和解缩的机制。我们在此表明，通过暴露于含有模仿体内浓度的组胺的酸性溶液，胞吐分泌颗粒的水合基质可以重新凝结至其原始体积。酸性组胺的再缩合在 1-10 mM 范围内开始，剂量反应曲线可通过 Hill 型方程准确预测，具有四个高度合作的结合位点和半最大浓度 [Hi++] = 3.9 mM。组胺的再缩合表现出对 pH 值（临界范围 pH 5.5-6.5）的 S 型依赖性，并且是完全可逆的。这些实验表明，组胺可能通过与颗粒基质的蛋白质-肝素复合物中的阴离子位点结合，引发颗粒基质的聚合结构从延伸的线圈到塌陷的球状状态的变化。这可能是了解分泌产物凝结成致密核心颗粒及其随后在胞吐作用时解凝结的有用模型。
We have investigated the mechanisms responsible for the condensation and decondensation of secretory products that occur in mast cell secretion. We show here that the hydrated matrix of an exocytosed secretory granule can be recondensed to its original volume by exposure to acidic solutions containing histamine at concentrations that mimic those found in vivo. Recondensation by acidic histamine began in the range of 1–10 mM with a dose response curve that was accurately predicted by a Hill type equation with four highly cooperative binding sites and a half maximum concentration of [Hi++] = 3.9 mM. Recondensation by histamine showed a sigmoidal dependency on pH (critical range pH 5.5–6.5) and was fully reversible. These experiments suggest that histamine, possibly by binding to anionic sites in the protein-heparin complex of the granule matrix, triggers a change in the polymeric structures of the granule matrix from an extended coil to a collapsed globular state. This may be a useful model for understanding the condensation of secretory products into dense core granules and their subsequent decondensation upon exocytosis.