Specific and nonspecific effects of protein kinase C on the epithelial Na (+) channel.
Specific and nonspecific effects of protein kinase C on the epithelial Na (+) channel.
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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。
DOI：
10.1085/jgp.115.5.559
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发表时间：
2000-05
影响因子：
3.8
通讯作者：
Awayda, MS
中科院分区：
文献类型：
--
作者：
Awayda, MS
利用非洲爪哇卵母细胞表达系统探讨了PKC(Away da，M.S.，I.I.Ismailov，B.K.Berdiev，C.M.Fuller，D.J.Benos)抑制克隆的大鼠上皮Na+通道(RENaC)的机制。1996年。J.Gen.Physiol.108：49-65)，并确定人类ENaC是否表现出类似的调节。通过阻抗分析间接测量膜面积，确定PKC激活对膜和/或通道转运的影响。表达hENaC的卵母细胞在超极化电压下表现出明显的激活。这种激活可以用时间常数(τ)和幅度(ΔI V)来描述的单一指数来拟合。在表达rENaC的卵母细胞中也观察到了类似但较小的激活幅度。这种激活很可能对应于前面描述的超极化电压对天然Na+通道门控的影响(Palmer，L.G.和G.Frindt。1996年。J.Gen.Physiol.107：35-45)。用100nM PMA刺激PKC可使表达hENaC的卵母细胞ΔIV在20min时降至基线的57.1±4.9%(n=6)。在表达rENaC的卵母细胞中也观察到了类似的效果。PMA使阿米洛利敏感的hENaC斜率电导(GNA)在30min时降至基线的21.7±7.2%(n=6)。这一下降与之前报道的rENaC相似。G-Na的降低是由于膜电容(Cm)和比电导(gm/cm)的降低。对Gm/cm的影响在15分钟内达到平台期，∼为基线的60%。这种下降可能是由于PKC抑制ENaC的特异性能力所致。另一方面，Cm的降低与ENaC无关，可能是PKC对膜转运的影响，正如在ENaC表达的卵母细胞和对照卵母细胞中观察到的那样。在较低的PMA浓度下(0.5 nM)，表达rENaC和hENaC的卵母细胞的cm变化较小，而gm和gm/cm的变化较大，表明对ENaC具有特异性作用。这些发现表明，PKC在ENaC上表现出多重和特异性的作用，在膜转运上也表现出非特异性的作用。此外，这些发现为评估PKC在非洲爪哇卵母细胞表达系统中的通道特异性作用提供了电生理学基础。
The Xenopus oocyte expression system was used to explore the mechanisms of inhibition of the cloned rat epithelial Na+ channel (rENaC) by PKC (Awayda, M.S., I.I. Ismailov, B.K. Berdiev, C.M. Fuller, and D.J. Benos. 1996. J. Gen. Physiol. 108:49–65) and to determine whether human ENaC exhibits similar regulation. Effects of PKC activation on membrane and/or channel trafficking were determined using impedance analysis as an indirect measure of membrane area. hENaC-expressing oocytes exhibited an appreciable activation by hyperpolarizing voltages. This activation could be fit with a single exponential, described by a time constant (τ) and a magnitude (ΔI V). A similar but smaller magnitude of activation was also observed in oocytes expressing rENaC. This activation likely corresponds to the previously described effect of hyperpolarizing voltage on gating of the native Na+ channel (Palmer, L.G., and G. Frindt. 1996. J. Gen. Physiol. 107:35–45). Stimulation of PKC with 100 nM PMA decreased ΔIV in hENaC-expressing oocytes to a plateau at 57.1 ± 4.9% (n = 6) of baseline values at 20 min. Similar effects were observed in rENaC-expressing oocytes. PMA decreased the amiloride-sensitive hENaC slope conductance (gNa) to 21.7 ± 7.2% (n = 6) of baseline values at 30 min. This decrease was similar to that previously reported for rENaC. This decrease of g Na was attributed to a decrease of membrane capacitance (C m), as well as the specific conductance (gm/Cm ). The effects on gm/Cm reached a plateau within 15 min, at ∼60% of baseline values. This decrease is likely due to the specific ability of PKC to inhibit ENaC. On the other hand, the decrease of Cm was unrelated to ENaC and is likely an effect of PKC on membrane trafficking, as it was observed in ENaC-expressing as well as control oocytes. At lower PMA concentrations (0.5 nM), smaller changes of Cm were observed in rENaC- and hENaC-expressing oocytes, and were preceded by larger changes of gm and by changes of gm/Cm, indicating specific effects on ENaC. These findings indicate that PKC exhibits multiple and specific effects on ENaC, as well as nonspecific effects on membrane trafficking. Moreover, these findings provide the electrophysiological basis for assessing channel-specific effects of PKC in the Xenopus oocyte expression system.
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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.95.6.3301
发表时间：
1998-03-17
影响因子：
11.1
作者：
Shimkets, RA;Lifton, R;Canessa, CM
通讯作者：
Canessa, CM
影响因子：
--
作者：
SILVER, RB;FRINDT, G;PALMER, LG
通讯作者：
PALMER, LG
影响因子：
19.6
作者：
EATON, DC;BECCHETTI, A;LING, BN
通讯作者：
LING, BN
影响因子：
3.4
作者：
CLAUSEN, C;LEWIS, SA;DIAMOND, JM
通讯作者：
DIAMOND, JM