CONNEXIN43 AND CONNEXIN45 FORM GAP-JUNCTIONS WITH DIFFERENT MOLECULAR PERMEABILITIES IN OSTEOBLASTIC CELLS
CONNEXIN43 AND CONNEXIN45 FORM GAP-JUNCTIONS WITH DIFFERENT MOLECULAR PERMEABILITIES IN OSTEOBLASTIC CELLS
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DOI：
10.1002/j.1460-2075.1994.tb06316.x
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发表时间：
1994-02-15
期刊：
影响因子：
11.4
通讯作者：
BEYER, EC
中科院分区：
文献类型：
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作者：
STEINBERG, TH;CIVITELLI, R;BEYER, EC
我们检测了两个大鼠成骨细胞系ROS 17/2.8和UMR 106-01中缝隙连接的表达和功能。缝隙连接蛋白在这两种细胞系中的表达模式是不同的：ROS细胞仅在其细胞表面表达连接蛋白43，而UMR细胞主要表达连接蛋白45。免疫沉淀和RNA印迹分析证实了这些连接蛋白的相对定量。显微注射的ROS细胞将荧光黄传递给许多邻近的细胞，但UMR细胞在这一标准下偶联能力很差。然而，UMR和ROS细胞都是电耦合的，这是双全细胞膜片钳技术的特征。这些研究表明，ROS细胞中的Cx43介导了小离子和大分子的细胞-细胞耦合，而UMR细胞中的Cx45只允许小离子通过。为了证明不同连接蛋白的单独表达可以解释UMR细胞缺乏染料偶联的原因，我们评估了Cx43或Cx45转染的UMR细胞的染料偶联。与未转染的UMR细胞相比，UMR/Cx43转染体具有高度的染料偶联性，但UMR/Cx45转染体的染料转移率没有增加。这些数据表明，不同的缝隙连接蛋白创建具有不同分子渗透性的通道；它们表明不同的连接蛋白允许不同类型的细胞之间的信号传递。
We examined the expression and function of gap junctions in two rat osteoblastic cell lines, ROS 17/2.8 and UMR 106-01. The pattern of expression of gap junction proteins in these two cell lines was distinct: ROS cells expressed only connexin43 on their cell surface, while UMR expressed predominantly connexin45. Immunoprecipitation and RNA blot analysis confirmed the relative quantitation of these connexins. Microinjected ROS cells passed Lucifer yellow to many neighboring cells, but UMR cells were poorly coupled by this criterion. Nevertheless, both UMR and ROS cells were electrically coupled, as characterized by the double whole cell patch-clamp technique. These studies suggested that Cx43 in ROS cells mediated cell-cell coupling for both small ions and larger molecules, but Cx45 in UMR cells allowed passage only of small ions. To demonstrate that the expression of different connexins alone accounted for the lack of dye coupling in UMR cells, we assessed dye coupling in UMR cells transfected with either Cx43 or Cx45. The UMR/Cx43 transfectants were highly dye coupled compared with the untransfected UMR cells, but the UMR/Cx45 transfectants demonstrated no increase in dye transfer. These data demonstrate that different gap junction proteins create channels with different molecular permeabilities; they suggest that different connexins permit different types of signalling between cells.