Palmitoylation of the Na/Ca exchanger cytoplasmic loop controls its inactivation and internalization during stress signaling.
Palmitoylation of the Na/Ca exchanger cytoplasmic loop controls its inactivation and internalization during stress signaling.
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DOI：
10.1096/fj.15-276493
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发表时间：
2015-11
期刊：
影响因子：
--
通讯作者：
Fuller W
中科院分区：
文献类型：
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作者：
Reilly L;Howie J;Wypijewski K;Ashford ML;Hilgemann DW;Fuller W
在许多细胞中，生电性Na/Ca交换器(NCX)介导对钠梯度变化高度敏感的双向钙运动。NCX1与心力衰竭和许多心律失常的发病机制有关。我们用树脂辅助捕获法测量了NCX1棕榈酰化，用全细胞电压钳技术测量了黄色荧光蛋白-NCX1融合蛋白的亚细胞定位，以及NCX1电流。大鼠NCX1在所有被检查的组织中基本上都是棕榈酰化的。NCX1胞内大环中的半胱氨酸739是NCX1棕榈酰化所必需的，也是充分的。NCX1的棕榈酰化发生在高尔基体中，并将NCX1的大调节细胞内环锚定在膜上。令人惊讶的是，棕榈酰化不会影响NCX1向表膜的运输或定位，也不会强烈影响NCX1的正常正向或反向运输方式。然而，不能棕榈酰化的交换器不能正常失活(在野生型交换器不活跃的条件下导致相当大的活性)，并且不促进货物依赖的内吞作用，这种内吞作用在强烈的G蛋白激活或大的钙瞬变之后内化50%的细胞表面。NCX1中的棕榈酰化半胱氨酸存在于所有脊椎动物和一些无脊椎动物的NCX同源物中。因此，NCX棕榈酰化在表达NCX蛋白的细胞中普遍调节钙稳态和膜域功能。-Reilly，L.，Howie，J.，Wypijesski，K.，Ashford，M.L.J.，Hilgemann，D.W.，Fuller，W.在胁迫信号传递过程中，Na/Ca交换器胞质环的棕榈酰化控制其失活和内化。
The electrogenic Na/Ca exchanger (NCX) mediates bidirectional Ca movements that are highly sensitive to changes of Na gradients in many cells. NCX1 is implicated in the pathogenesis of heart failure and a number of cardiac arrhythmias. We measured NCX1 palmitoylation using resin-assisted capture, the subcellular location of yellow fluorescent protein–NCX1 fusion proteins, and NCX1 currents using whole-cell voltage clamping. Rat NCX1 is substantially palmitoylated in all tissues examined. Cysteine 739 in the NCX1 large intracellular loop is necessary and sufficient for NCX1 palmitoylation. Palmitoylation of NCX1 occurs in the Golgi and anchors the NCX1 large regulatory intracellular loop to membranes. Surprisingly, palmitoylation does not influence trafficking or localization of NCX1 to surface membranes, nor does it strongly affect the normal forward or reverse transport modes of NCX1. However, exchangers that cannot be palmitoylated do not inactivate normally (leading to substantial activity in conditions when wild-type exchangers are inactive) and do not promote cargo-dependent endocytosis that internalizes 50% of the cell surface following strong G-protein activation or large Ca transients. The palmitoylated cysteine in NCX1 is found in all vertebrate and some invertebrate NCX homologs. Thus, NCX palmitoylation ubiquitously modulates Ca homeostasis and membrane domain function in cells that express NCX proteins.—Reilly, L., Howie, J., Wypijewski, K., Ashford, M. L. J., Hilgemann, D. W., Fuller, W. Palmitoylation of the Na/Ca exchanger cytoplasmic loop controls its inactivation and internalization during stress signaling.