Interactions between ankyrin-G, Plakophilin-2, and Connexin43 at the cardiac intercalated disc.
Interactions between ankyrin-G, Plakophilin-2, and Connexin43 at the cardiac intercalated disc.
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DOI：
10.1161/circresaha.111.247023
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发表时间：
2011-07-08
影响因子：
20.1
通讯作者：
Delmar M
中科院分区：
文献类型：
--
作者：
Sato PY;Coombs W;Lin X;Nekrasova O;Green KJ;Isom LL;Taffet SM;Delmar M
早期对间盘的描述定义了三种结构，它们都与细胞间的通讯有关：桥粒、缝隙连接和贴壁连接。目前的证据表明，不参与提供细胞间物理连续体的分子也填充着嵌入的间盘。其中的关键是电压门控钠通道(VGSC)复合体。该复合体的重要组成部分是细胞骨架接头蛋白AnkG(AnkG)。为了验证AnkG与桥粒和缝隙连接分子合作，并在心脏细胞间通讯中发挥作用的假设。我们利用显微镜、免疫化学、膜片钳和光学图谱相结合的方法来评估AnkG、亲血小板蛋白2(PKP2)和连接蛋白43(Cx43)的相互作用。大鼠心脏裂解液的免疫共沉淀研究证明了这三个分子之间的关联。利用siRNA技术，我们证明AnkG表达的缺失导致了PKP2和Cx43的亚细胞分布和/或丰度的显著变化，以及细胞间黏附强度和电偶联的降低。PKP2对AnkG和NaV1.5的调节作用也得到证实。最后，在AnkG沉默的细胞中的光学标测实验表明，观察到速率依赖的激活阻断的最小频率发生了移动。这些实验支持这样的假设，即AnkG是间盘的关键功能成分，位于通常被认为是独立的三个复合体的交叉点：VGSC、缝隙连接和心脏桥粒。对遗传性心律失常(如致心律失常性右室心肌病；ARVC)的病理生理学意义进行了讨论。
The early description of the intercalated disc defined three structures, all of them involved in cell-cell communication: desmosomes, gap junctions and adherens junctions. Current evidence demonstrates that molecules not involved in providing a physical continuum between cells, also populate the intercalated disc. Key among them is the voltage-gated sodium channel (VGSC) complex. An important component of this complex is the cytoskeletal adaptor protein ankyrin-G (AnkG). To test the hypothesis that AnkG partners with desmosome and gap junction molecules, and exerts a functional effect on intercellular communication in the heart. We utilized a combination of microscopy, immunochemistry, patch clamp and optical mapping to assess the interactions between AnkG, plakophilin-2 (PKP2) and Connexin43 (Cx43). Co-immunoprecipitation studies from rat heart lysate demonstrated associations between the three molecules. Using siRNA technology we demonstrated that loss of AnkG expression caused significant changes in subcellular distribution and/or abundance of PKP2 and Cx43, as well as a decrease in intercellular adhesion strength and electrical coupling. Regulation of AnkG and of Nav1.5 by PKP2 was also demonstrated. Finally, optical mapping experiments in AnkG-silenced cells demonstrated a shift in the minimal frequency at which rate-dependence activation block was observed. These experiments support the hypothesis that AnkG is a key functional component of the intercalated disc, at the intersection of three complexes often considered independent: the VGSC, gap junctions and the cardiac desmosome. Possible implications to the pathophysiology of inherited arrhythmias (such as arrhythmogenic right ventricular cardiomyopathy; ARVC) are discussed.