Serum‐stimulated changes in calcium transport and distribution in mouse 3T3 cells and their modification by dibutyryl cyclic AMP
Serum‐stimulated changes in calcium transport and distribution in mouse 3T3 cells and their modification by dibutyryl cyclic AMP
复制标题
血清刺激的小鼠 3T3 细胞中钙转运和分布的变化及其通过二丁酰环 AMP 的修饰
DOI：
10.1002/jcp.1040950110
复制
发表时间：
1978
影响因子：
5.6
通讯作者：
Flavia Zorgniotti
中科院分区：
文献类型：
--
作者：
J. Tupper;M. Rosso;B. Hazelton;Flavia Zorgniotti
血清刺激静止的3T3细胞使细胞恢复到增殖状态。在血清刺激这些细胞后，研究了钙含量、转运和分布在G1期和S期过渡期间的变化。45Ca交换数据表明至少有两个动力学定义的Ca胞室；一种快速交换的成分可能代表被EGTA去除的表面Ca，另一种缓慢交换的成分可能代表细胞质上的Ca。以前的研究（Tupper和Zorgniotti， 1977）表明，3T3细胞的静止方式是以表面Ca成分的大量增加为特征的。目前的数据表明，该成分在血清刺激后迅速丧失。此外，血清诱导钙流入细胞质室的量增加8倍，并降低钙的单向流出率系数。钙摄取增加在大约6小时（G1中期）达到峰值，并伴有细胞钙的平行增加。在细胞进入S期（10-12小时）之前，钙摄取下降。随后是细胞质钙水平的缓慢下降。同时加入新鲜血清和0.5 mM二丁基cAMP可抑制细胞进入S期。在这些条件下，表面钙的损失不会被阻止。然而，0.5 mM二丁基cAMP的存在抑制了钙摄取的增加，反过来，减少了血清刺激后细胞钙的增加。相比之下，低水平的二丁基cAMP （0.1 mM）促进了G1期的进展，但也降低了细胞的钙摄取和钙含量。这些数据表明，血清诱导的Ca含量和转运的变化与细胞内环核苷酸水平和G1期的进展有关，细胞外cAMP升高剂可能以浓度依赖的方式增强或抑制这些相互作用。
Serum stimulation of quiescent 3T3 cells returns the cells to a proliferative state. Changes in Ca content, transport and distribution during the transition through G1 and S phase have been investigated following serum stimulation of these cells. 45Ca exchange data indicate at least two kinetically defined cellular compartments for Ca; a rapidly exchanging component presumably representing surface Ca which is removable by EGTA and a slowly exchanging component presumably representing cytoplasmically located Ca. Previous studies (Tupper and Zorgniotti, 1977) indicate that the approach to quiescence in the 3T3 cells is characterized by a large increase in the surface Ca component. The present data demonstrate that this component is rapidly lost following serum stimulation. Furthermore, the serum induces an 8‐fold increase in Ca influx into the cytoplasmic compartment and a reduction in the unidirectional efflux rate coefficient for Ca. The increased Ca uptake peaks at approximately six hours (mid G1) and is accompanied by a parallel increase in cellular Ca. Prior to entrance of the cells into S phase (10—12 hours), Ca uptake declines. This is followed by a slower decline in cytoplasmic Ca levels. Simultaneous addition of fresh serum plus 0.5 mM dibutyryl cAMP inhibits the entrance of the cells into S phase. Under these conditions the loss of surface Ca is not blocked. However, the presence of 0.5 mM dibutyryl cAMP inhibits the increase in Ca uptake and, in turn, diminishes the increase in cellular Ca following serum stimulation. In contrast, a low level of dibutyryl cAMP (0.1 mM) enhances progression through G1 phase but also reduces both Ca uptake and Ca content of the cells. The data suggest that the serum induced changes in Ca content and transport are linked to intracellular cyclic nucleotide levels and progression through G1 phase and that extracellular cAMP elevating agents may enhance or inhibit these interactions in a concentration dependent manner.