Formation of heterotypic gap junction channels by connexins 40 and 43
Formation of heterotypic gap junction channels by connexins 40 and 43
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DOI：
10.1161/01.res.86.2.e42
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发表时间：
2000-02-04
影响因子：
20.1
通讯作者：
Brink, PR
中科院分区：
文献类型：
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作者：
Valiunas, V;Weingart, R;Brink, PR
在稳定状态下，表达连接蛋白(Cx)40抗Cx43的细胞(Cx43-RIN、Cx40-HeLa和Cx43-HeLa)之间形成的缝隙连接显示出一种关系，g(J)=f(V-j)，其典型的不对称行为类似于先前报道的其他异型通道的不对称行为(缝隙连接电导[g(J)]；跨连接电压[V-j])。通道的单位电导对V-j的极性很敏感。当Cx43细胞正阶跃或Cx40细胞负阶跃(V-j=70 mV)时，主态电导为61ps；反之，电导为100pS。这些异型通道对羧基荧光素具有通透性。此外，还展示了另外两种异型形式，以证明内源性Cx45的表达不能解释结果。异型Cx40-Cx43通道的发现可能对心脏电脉冲的传播有一定的意义。例如，它们可能有助于减缓通过浦肯野纤维和心室肌之间的连接的脉冲传播。本文全文可在http://www.circresaha.org.上查阅
Gap junctions formed between transfected cells expressing connexin (Cx) 40 anti Cx43 (Cx43-RIN, Cx40-HeLa, and Cx43-HeLa) revealed a relationship, g(j)=f(V-j), at steady state, that is typified by a nonsymmetrical behavior similar to that previously reported for other heterotypic channels (gap junction conductance [g(j)]; transjunctional voltage [V-j]). The unitary conductance of the channels was sensitive to the polarity of V-j. A main state conductance of 61 pS was found when the Cx43 cell was stepped positively or the Cx40 cell negatively (V-j=70 mV); the reverse polarities yielded a conductance of 100 pS. These heterotypic channels were permeable to carboxyfluorescein. In addition, two other heterotypic forms are illustrated to demonstrate that endogenous Cx45 expression cannot explain the results. The demonstration of heterotypic Cx40-Cx43 channels may have implications for the propagation of the electrical impulse in heart. For example, they may contribute to the slowing of the impulse propagation through the junctions between Purkinje fibers and ventricular muscle. The full text of this article is available at http://www.circresaha.org.