EHD3-dependent endosome pathway regulates cardiac membrane excitability and physiology.
EHD3-dependent endosome pathway regulates cardiac membrane excitability and physiology.
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DOI：
10.1161/circresaha.115.304149
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发表时间：
2014-06-20
影响因子：
20.1
通讯作者：
Mohler PJ
中科院分区：
文献类型：
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作者：
Curran J;Makara MA;Little SC;Musa H;Liu B;Wu X;Polina I;Alecusan JS;Wright P;Li J;Billman GE;Boyden PA;Gyorke S;Band H;Hund TJ;Mohler PJ
心脏功能依赖于膜离子通道、转运体、泵和激素受体的协调活动，以动态调节膜电化学梯度，以响应急性和慢性应激。虽然我们对膜蛋白的了解在过去十年中迅速发展，但我们对控制整体膜蛋白运输和定位的亚细胞途径的理解是有限的，而且基本上没有在体内研究。在心脏方面，据我们所知，没有体内机制研究直接将内核体机制与心脏生理学联系起来。定义基于内核体的细胞机制在心脏膜蛋白运输、心肌细胞兴奋性和心脏生理学中的体内作用。我们确定基于内体的EHD3途径对心脏生理至关重要。EHD3−/−心脏表现出结构和功能缺陷，包括心动过缓和心率变异性、传导阻滞和对肾上腺素能刺激的迟钝反应。在机制上，EHD3对膜蛋白运输至关重要，因为EHD3 - / -肌细胞显示Na/Ca交换器和Cav1.2的表达/定位减少，同时INCX和ICa，L的平行减少。在功能上，EHD3−/−肌细胞表现出肌浆网[Ca]增加，火花频率增加，锚蛋白b （EHD3和Na/Ca交换器的结合伙伴）的表达/定位减少。最后，我们发现体内EHD3−/−缺陷是由于EHD3的心脏特异性作用，因为心脏选择性EHD3缺陷的小鼠表现出结构和电表型。这些数据为膜蛋白靶向和心脏生理学中基于内体的通路的关键作用提供了新的见解。EHD3是心脏蛋白质运输的关键组成部分，对于选择维持兴奋性的细胞蛋白的适当膜靶向至关重要。
Cardiac function is dependent on the coordinate activities of membrane ion channels, transporters, pumps, and hormone receptors to dynamically tune the membrane electrochemical gradient in response to acute and chronic stress. While our knowledge of membrane proteins has rapidly advanced over the past decade, our understanding of the subcellular pathways governing the trafficking and localization of integral membrane proteins is limited, and essentially unstudied in vivo. In heart, to our knowledge, there are no in vivo mechanistic studies that directly link endosome-based machinery with cardiac physiology. Define the in vivo roles of endosome-based cellular machinery for cardiac membrane protein trafficking, myocyte excitability, and cardiac physiology. We identify the endosome-based EHD3 pathway as essential for cardiac physiology. EHD3−/− hearts display structural and functional defects including bradycardia and rate variability, conduction block, and blunted response to adrenergic stimulation. Mechanistically, EHD3 is critical for membrane protein trafficking, as EHD3−/− myocytes display reduced expression/localization of Na/Ca exchanger and Cav1.2 with a parallel reduction in INCX and ICa,L. Functionally, EHD3−/− myocytes show increased sarcoplasmic reticulum [Ca], increased spark frequency, and reduced expression/localization of ankyrin-B, a binding partner for EHD3 and Na/Ca exchanger. Finally, we show that in vivo EHD3−/− defects are due to cardiac-specific roles of EHD3 as mice with cardiac-selective EHD3 deficiency demonstrate both structural and electrical phenotypes. These data provide new insight into the critical role of endosome-based pathways in membrane protein targeting and cardiac physiology. EHD3 is a critical component of protein trafficking in heart and is essential for the proper membrane targeting of select cellular proteins that maintain excitability.