A METABOLITE-REGULATED POTASSIUM CHANNEL IN RAT PANCREATIC-B CELLS
A METABOLITE-REGULATED POTASSIUM CHANNEL IN RAT PANCREATIC-B CELLS
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DOI：
10.1073/pnas.83.18.7119
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发表时间：
1986-09-01
影响因子：
11.1
通讯作者：
MCDANIEL, ML
中科院分区：
文献类型：
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作者：
MISLER, S;FALKE, LC;MCDANIEL, ML
在来自分散的朗格汉斯大鼠胰岛的 B 细胞中，我们发现了一个内向整流的电压无关 K+ 通道，其行为与示踪通量和微电极记录研究中发现的代谢调节钾渗透性 (PK) 相似。在细胞附着的膜片中，当将几种底物（葡萄糖、甘露糖、亮氨酸或甘油醛）中的任何一种添加到细胞的沐浴液中时，通道会关闭，但在添加适当的代谢抑制剂后会重新打开，从而阻止该底物的利用。在从内向外的切除斑块中，通过向“细胞质”溶液中添加微摩尔浓度的 ATP，可以关闭具有几乎相同动力学特征的 K+ 通道。添加 ADP 可以改变通道活性的 ATP 敏感性，表明核苷酸结合位点存在竞争。这些结果表明存在由细胞内 ATP 浓度或 ATP/ADP 浓度比门控的代谢调节 K+ 通道。
In B cells from dispersed rat islet of Langerhans we have identified an inward rectifying voltage-independent K+ channel whose behavior parallels the metabolically regulated potassium permeability (PK) found in tracer flux and microelectrode recording studies. In cell-attached patches of membrane, the channel is closed when any one of several substrates (glucose, mannose, leucine, or glyceraldehyde) is added to the cell''s bathing solution but is reopened on addition of an appropriate metabolic inhibitor, which prevents utilization of that substrate. In inside-out excised patches, a K+ channel with nearly identical kinetic features is closed by addition of micromolar concentrations of ATP to the "cytoplasmic" solution. The ATP sensitivity of channel activity is modified by addition of ADP, suggesting competition at a nucleotide binding site. These results suggest the presence of a metabolically regulated K+ channel gated by intracellular concentrations of ATP or the ratio of ATP/ADP concentrations.