Changes in the phosphorylation states of connexin43 in myoepithelial cells of lactating rat mammary glands.
Changes in the phosphorylation states of connexin43 in myoepithelial cells of lactating rat mammary glands.
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哺乳期大鼠乳腺肌上皮细胞连接蛋白43磷酸化状态的变化。
DOI：
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发表时间：
1997
影响因子：
6.6
通讯作者：
Y. Shibata
中科院分区：
文献类型：
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作者：
I. Yamanaka;A. Kuraoka;T. Inai;T. Ishibashi;Y. Shibata
利用特异性抗体和cDNA探针，我们研究了一个主要的间隙连接蛋白，连接蛋白43（Cx43），在大鼠乳腺在怀孕和哺乳期的表达模式。免疫荧光双标显示，α-平滑肌肌动蛋白阳性细胞中存在Cx43的标记，提示肌上皮细胞之间通过Cx43形成的缝隙连接相互连接。分娩后，Cx43标记的斑块扩大，强度增加。北方和Western印迹分析证实了分娩当天在mRNA和蛋白水平上Cx43的显著诱导。Cx43 mRNA转录立即下降，而Cx43蛋白的增加持续了几天。在怀孕期间，免疫印迹显示在43和45 kDa几乎等量的两条带。递送后，45-kDa条带的强度逐渐增加，伴随着43-kDa条带的降低。从泌乳的第六天，Cx43总是检测到作为一个单一的带在45 kDa。碱性磷酸酶处理的免疫沉淀的Cx43显示，这两个带代表磷酸化的形式，从而表明，Cx43是自然磷酸化，并改变其磷酸化状态在哺乳期阶段。这些结果表明，诱导Cx43的磷酸化状态的变化在大鼠乳腺肌上皮细胞的泌乳功能中起着重要作用。本文首次报道了Cx43磷酸化状态在体内生理过程中的变化。
Using specific antibodies and cDNA probe, we examined the expression pattern of a major gap junction protein, connexin43 (Cx43), in rat mammary glands during pregnancy and lactation. Double immuno-fluorescence revealed that the labeling of Cx43 was superimposed in the alpha-smooth muscle actin-positive cells, suggesting that myoepithelial cell were interconnected by gap junctions formed of Cx43. Just after delivery, the Cx43-labeled plaques were enlarged and increased in intensity. Northern and Western blot analyses confirmed the dramatic induction of Cx43 at both mRNA and protein levels on the day of parturition. Cx43 mRNA transcript immediately declined, while the increase of Cx43 protein continued for a few days. During pregnancy, immunoblots showed two bands of almost equal amounts at 43 and 45 kDa. Following delivery, the 45-kDa band gradually increased in intensity with a concomitant decrease of the 43-kDa band. From the sixth day of lactation, Cx43 was always detected as a single band at 45 kDa. Alkaline phosphatase treatment of immunoprecipitated Cx43 revealed that both bands represented phosphorylated forms, thus indicating that Cx43 was naturally phosphorylated and that it altered its phosphorylation states during lactation stages. These results suggest that the induction of Cx43 with the changes in the phosphorylation states plays an important role in the lactating function of myoepithelial cells in rat mammary glands. This is the first report on the changes of Cx43 phosphorylation states during physiological stages in vivo.