ENaC-membrane interactions: regulation of channel activity by membrane order.
ENaC-membrane interactions: regulation of channel activity by membrane order.
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DOI：
10.1085/jgp.200308983
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发表时间：
2004-06
期刊：
影响因子：
--
通讯作者：
Hill WG
中科院分区：
文献类型：
--
作者：
Awayda MS;Shao W;Guo F;Zeidel M;Hill WG
最近，据报道，上皮Na+通道（ENaC）受温度调节（Askwith，C.C.，C. J.本森，M. J.威尔士和P.M.斯奈德。2001. Proc. Natl. Acad. Sci. USA. 98：6459-6463）。由于这些温度的变化会影响膜脂质的顺序和脂质-蛋白质相互作用，我们测试了ENaC活性可以通过膜脂质相互作用来调节的假设。两种方法被用来调节膜各向异性，脂质顺序依赖性参数。非药理学方法使用温度变化，而药理学方法使用氯丙嗪（CPZ）（一种已知可降低膜有序性的药物）和Gd+3。实验使用表达人ENaC的非洲爪蟾卵母细胞。阻抗分析的方法被用来确定是否改变脂质顺序的影响间接改变ENaC电导通过膜面积的变化。通过电子显微镜研究的卵母细胞膜显微照片的定量形态进一步证实了这些数据。我们报告双相效应的冷却（刺激，然后抑制）hENaC电导。这些影响相对缓慢（分钟），并从实际的浴温变化延迟。峰值刺激发生在计算的Tmax为15.2时。在低于Tmax的温度下，ENaC电导随冷却而被抑制。温度对g Na的影响与在非洲爪蟾卵母细胞内源性离子通道上观察到的不同，在非洲爪蟾卵母细胞内源性离子通道上，膜电导随温度呈单指数下降（t = 6.2°C）。在卵母细胞内和细胞外[Na+]减少的情况下也观察到类似的效应，从而排除了自我或反馈抑制的效应。此外，CPZ或机械敏感性通道阻滞剂，Gd+3，引起抑制ENaC。Gd+3的作用也归因于其分配到外膜瓣叶和降低各向异性的能力。没有温度，CPZ，或Gd+3的影响伴随着膜面积的变化，表明可能没有对通道运输的影响。然而，CPZ和Gd+3以与温度相反的方式改变膜电容，与对膜介电性质的影响一致。Gd+3和CPZ的可逆效应也可以通过冷却和将这些试剂捕获在硬化膜中来阻断，为它们的作用机制提供了进一步的证据。我们的研究结果证明了ENaC的一种新的调节机制。
Recently, it was reported that the epithelial Na+ channel (ENaC) is regulated by temperature (Askwith, C.C., C.J. Benson, M.J. Welsh, and P.M. Snyder. 2001. Proc. Natl. Acad. Sci. USA. 98:6459–6463). As these changes of temperature affect membrane lipid order and lipid–protein interactions, we tested the hypothesis that ENaC activity can be modulated by membrane lipid interactions. Two approaches were used to modulate membrane anisotropy, a lipid order–dependent parameter. The nonpharmacological approach used temperature changes, while the pharmacological one used chlorpromazine (CPZ), an agent known to decrease membrane order, and Gd+3. Experiments used Xenopus oocytes expressing human ENaC. Methods of impedance analysis were used to determine whether the effects of changing lipid order indirectly altered ENaC conductance via changes of membrane area. These data were further corroborated with quantitative morphology on micrographs from oocytes membranes studied via electron microscopy. We report biphasic effects of cooling (stimulation followed by inhibition) on hENaC conductance. These effects were relatively slow (minutes) and were delayed from the actual bath temperature changes. Peak stimulation occurred at a calculated Tmax of 15.2. At temperatures below Tmax, ENaC conductance was inhibited with cooling. The effects of temperature on g Na were distinct from those observed on ion channels endogenous to Xenopus oocytes, where the membrane conductance decreased monoexponentially with temperature (t = 6.2°C). Similar effects were also observed in oocytes with reduced intra- and extracellular [Na+], thereby ruling out effects of self or feedback inhibition. Addition of CPZ or the mechanosensitive channel blocker, Gd+3, caused inhibition of ENaC. The effects of Gd+3 were also attributed to its ability to partition into the outer membrane leaflet and to decrease anisotropy. None of the effects of temperature, CPZ, or Gd+3 were accompanied by changes of membrane area, indicating the likely absence of effects on channel trafficking. However, CPZ and Gd+3 altered membrane capacitance in an opposite manner to temperature, consistent with effects on the membrane-dielectric properties. The reversible effects of both Gd+3 and CPZ could also be blocked by cooling and trapping these agents in the rigidified membrane, providing further evidence for their mechanism of action. Our findings demonstrate a novel regulatory mechanism of ENaC.
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蛋白激酶C对上皮Na（+）通道的特异性和非特异性作用。
影响因子：
3.8
作者：
Awayda, MS
通讯作者：
Awayda, MS
DOI：
10.1085/jgp.27.1.37
发表时间：
1943-09-20
期刊：
The Journal of general physiology
影响因子：
--
作者：
Goldman DE
通讯作者：
Goldman DE
DOI：
10.1085/jgp.112.2.97
发表时间：
1998-08
期刊：
The Journal of general physiology
影响因子：
--
作者：
Awayda MS;Subramanyam M
通讯作者：
Subramanyam M
DOI：
10.1073/pnas.111155398
发表时间：
2001-05-22
影响因子：
11.1
作者：
Askwith, CC;Benson, CJ;Snyder, PM
通讯作者：
Snyder, PM
影响因子：
2
作者：
Aguilella, VM;Bezrukov, SM
通讯作者：
Bezrukov, SM