期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：20
页码：6275-6279
DOI：10.1073/pnas.79.20.6275
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The stimulation of DNA synthesis in cultures of Swiss 3T3 cells by vasopressin, epidermal growth factor, and insulin added in serum-free medium is strikingly dependent on the intracellular K+ content or concentration. The relationship between these parameters is sigmoid; DNA synthesis commences only when the intracellular K+ increases above a certain threshold level (0.56 mumol/mg of protein; 90 mM). Addition of K+ to K+- depleted cultures reverses the block on DNA synthesis after a lag period of at least 8 hr. The sigmoid dependence of DNA synthesis on intracellular K+ is generated in early G1 phase rather than at the G1/S boundary. The effects of K+ on the G1-S transition are, at least in part, exerted through its control of protein synthesis. In serum-free medium, the K+ content is close to the threshold required for allowing a mitogenic response. The findings suggest that a small change in the intracellular K+ level can influence the ability of these cells to initiate DNA synthesis in serum-free medium.
