Activation of rat basophilic leukemia cells. Temporal identification of the signal calcium influx mediated by the receptor-operated channel pathway.
Activation of rat basophilic leukemia cells. Temporal identification of the signal calcium influx mediated by the receptor-operated channel pathway.
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大鼠嗜碱性白血病细胞的激活。
DOI：
10.1111/j.1432-1033.1988.tb13841.x
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Rivnay,B
中科院分区：
文献类型：
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作者：
Ran,S;Rivnay,B
在随后的洗涤步骤中排除阳离子损失的条件下，对抗原诱导的 45 钙流入大鼠嗜碱性白血病 (RBL) 细胞进行了检查，重点是早期时域。此类制剂表现出明显的、时间上独立的流入峰值，在 3 分钟时达到峰值，随后出现大量流出。这种内化的 45 Ca 2+ 接近毫摩尔总细胞内浓度，因此被隔离或与细胞内成分（蛋白质）结合。这种流入的幅度与低受体占用率下的 IgE 受体占用率成线性比例，并且对抗过敏药物色甘酸敏感。此外，对色甘酸的最大摄取和最大敏感性的时间与这些细胞中的 Quin-2 信号相关，并且初始脱颗粒模式与 45Ca2+ 摄取曲线的趋势有一些相似之处。这些特性表明，2-3 分钟的早期峰值，而不是任何后来的 45Ca2+ 吸收，构成了初始信号 Ca2+ 库。色甘酸对 45Ca2+ 吸收的最大明显抑制约为 65%，并且需要与细胞预孵育 10-15 分钟。抑制作用仅限于 3 分钟处的峰值，表明超过 5-6 分钟的示踪剂掺入主要涉及由受体聚集触发的其他池或途径，但仅与通道活动或信号本身间接相关。在完整细胞上测量的早期峰值与在含有纯化的 IgE 受体和纯化的色甘酸结合蛋白的重构平面双层上测量的单通道电导之间发现了定量相似性 [Corcia, A. 等人，2017]。 (1986)EMBO J. 5, 849–854]。这以及色甘酸的作用支持这样的假设：色甘酸结合蛋白是参与这种早期流入的主要成分，或者流入是信号钙质量的主要途径。
Antigen‐induced45calcium influx into rat basophilic leukemia (RBL) cells was examined with emphasis on the early time domain under conditions that exclude loss of the cation during the subsequent washing step. Such preparations demonstrate a distinct, temporally separate influx peaking at 3 min, followed by a substantial efflux. This internalized45Ca2+approaches millimolar total intracellular concentration and is therefore either sequestered or becomes bound to intracellular components (proteins). The amplitude of this influx is linearly proportional to IgE‐receptor occupancy at low receptor occupancies, and is sensitive to the anti‐allergic drug cromolyn. Furthermore, the timing of both the maximal uptake and the maximal susceptibility to cromolyn correlates with the Quin‐2 signal in these cells, and the initial degranulation pattern bears some resemblance to trends in the45Ca2+uptake curve. These qualities suggest that the early peak at 2–3 min, rather than any later45Ca2+uptake, comprises the initial signalling Ca2+pool. Maximal apparent inhibition by cromolyn for45Ca2+uptake was about 65% and required a 10–15‐min preincubation with the cells. The inhibitory effect was limited to the peak at 3 min, suggesting that tracer incorporation beyond 5–6 min largely involves other pools or pathways, triggered by receptor aggregation, yet only indirectly related to channel activity or to the signal proper. A quantitative similarity was found between the early peak measured on intact cells and the single channel conductance measured on reconstituted planar bilayers containing the purified receptor for IgE and the purified cromolyn‐binding protein [Corcia, A. et al. (1986)EMBO J. 5, 849–854]. This, as well as the effects of cromolyn, support the assumption that cromolyn‐binding protein is a major constituent involved in this early influx, or that influx is a principal pathway for the signaling calcium mass.