Stimulation by serum of the Na+/H+ antiporter in quiescent pig kidney epithelial (LLC-PK1) cells and role of the antiporter in the reinitiation of DNA synthesis.
Stimulation by serum of the Na+/H+ antiporter in quiescent pig kidney epithelial (LLC-PK1) cells and role of the antiporter in the reinitiation of DNA synthesis.
复制标题
血清对静止猪肾上皮 (LLC-PK1) 细胞中 Na /H 反向转运蛋白的刺激以及反向转运蛋白在重新启动 DNA 合成中的作用。
DOI：
10.1002/jcp.1041320125
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发表时间：
1987
影响因子：
5.6
通讯作者：
Adelberg,EA
中科院分区：
文献类型：
--
作者：
Haggerty,JG;Agarwal,N;Amsler,K;Slayman,CW;Adelberg,EA
LLC-PK1细胞可以通过剥夺血清6天而进入经典的静止状态。此时，[3H]-胸苷脉冲标记显示只有 3% 的细胞正在合成 DNA，但可以用血清刺激静止细胞，使其在 G1 早期的某个点重新进入细胞周期。静止期间阿米洛利敏感的 22Na+ 摄取率（作为 Na+/H+ 反向转运蛋白的衡量标准）相对较低；添加血清后 4 小时内升高 2 至 3 倍。这种反向转运蛋白活性的增加似乎是在没有碳酸氢盐的情况下恢复 DNA 合成所必需的，因为当将血清添加到无碳酸氢盐的培养基中的细胞中时，乙基异丙基阿米洛利 (EIPA) 会阻止 [3H]-胸苷掺入。然而，在碳酸氢盐存在的情况下，EIPA 对 [3H]-胸苷掺入没有影响，表明在这些条件下另一种（碳酸氢盐依赖性）转运系统可以替代反向转运蛋白。
LLC‐PK1cells can be brought into a classical quiescent state by depriving them of serum for 6 days. At this time, pulse‐labeling with [3H]‐thymidine shows that only 3% of the cells are synthesizing DNA, but the quiescent cells can be stimulated with serum to re‐enter the cell cycle at a point early in G1. The rate of amiloride‐sensitive22Na+uptake (as a measure of the Na+/H+antiporter) is relatively low during quiescence; it rises 2‐ to 3‐fold within 4 h after serum addition. This increase in antiporter activity appears to be required for the resumption of DNA synthesis in the absence of bicarbonate, because ethylisopropylamiloride (EIPA) blocks [3H]‐thymidine incorporation when serum is added to cells in bicarbonate‐free medium. In the presence of bicarbonate, however, EIPA has no effect on [3H]‐thymidine incorporation, indicating that another (bicarbonate‐dependent) transport system can substitute for the antiporter under these conditions.