A New Kindred With Pseudohypoaldosteronism Type II and a Novel Mutation (564D>H) in the Acidic Motif of the WNK4 Gene
A New Kindred With Pseudohypoaldosteronism Type II and a Novel Mutation (564D>H) in the Acidic Motif of the WNK4 Gene
复制标题
具有 II 型假性醛固酮减少症的新家族和 WNK4 基因酸性基序中的新突变 (564D>H)
作者：
Amir P. Golbang;M. Murthy;Abbas. G. Hamad;Che;G. Cope;W. V. van’t Hoff;Alan Cuthbert;K. O’Shaughnessy
我们发现了一个新的家族综合征的高血压和高钾血症（假性醛固酮减少症II型或戈登综合征）包含一个受影响的父亲和儿子。突变分析证实了外显子7内的单个杂合G至C取代（1690 G>C），其导致WNK 4的酸性基序内的错义突变（564 D>H）。我们通过在非洲爪蟾卵母细胞中与NaCl协同转运蛋白（NCCT）或内向整流K通道（ROMK）共表达证实了这种新突变的功能。野生型WNK 4对表达NCCT的非洲爪蟾卵母细胞22 Na+通量的抑制达90%（P<0.001），而564 D>H突变体对NCCT的22 Na+通量无明显抑制作用。在表达ROMK的卵母细胞中，野生型WNK 4在+20 mV的保持电位下对通过ROMK的稳态电流产生>50%的抑制（P<0.001）。564 D>H突变体产生了稳态电流的进一步抑制，达到野生型WNK 4的60%至70%。使用荧光标记的NCCT（增强的青色荧光蛋白-NCCT）和ROMK（增强的绿色荧光蛋白-ROMK）来定量卵母细胞膜中蛋白质的表达，似乎564 D>H突变的功能效应可以通过NCCT和ROMK的表面表达的改变来解释。与野生型WNK 4相比，WNK 4 564 D>H导致NCCT的细胞表面表达增加，但ROMK的表达减少。这项工作证实了WNK 4中的新型错义突变，564 D>H，具有功能活性，并进一步强调了WNK 4的酸性基序中单个残基上的电荷转换如何影响其与噻嗪敏感靶点NCCT和钾通道ROMK的相互作用。
We identified a new kindred with the familial syndrome of hypertension and hyperkalemia (pseudohypoaldosteronism type II or Gordon’s syndrome) containing an affected father and son. Mutation analysis confirmed a single heterozygous G to C substitution within exon 7 (1690G>C) that causes a missense mutation within the acidic motif of WNK4 (564D>H). We confirmed the function of this novel mutation by coexpressing it in Xenopus oocytes with either the NaCl cotransporter (NCCT) or the inwardly rectifying K-channel (ROMK). Wild-type WNK4 inhibits 22Na+ flux in Xenopus oocytes expressing NCCT by ≈90% (P<0.001), whereas the 564D>H mutant had no significantly inhibitory effect on flux through NCCT. In oocytes expressing ROMK, wild-type WNK4 produced >50% inhibition of steady-state current through ROMK at a +20-mV holding potential (P<0.001). The 564D>H mutant produced further inhibition with steady-state currents to some 60% to 70% of those seen with the wild-type WNK4. Using fluorescent-tagged NCCT (enhanced cyan fluorescent protein–NCCT) and ROMK (enhanced green fluorescent protein–ROMK) to quantify the expression of the proteins in the oocyte membrane, it appears that the functional effects of the 564D>H mutation can be explained by alteration in the surface expression of NCCT and ROMK. Compared with wild-type WNK4, WNK4 564D>H causes increased cell surface expression of NCCT but reduced expression of ROMK. This work confirms that the novel missense mutation in WNK4, 564D>H, is functionally active and highlights further how switching charge on a single residue in the acid motif of WNK4 affects its interaction with the thiazide-sensitive target NCCT and the potassium channel ROMK.
WNK 激酶和原发性高血压。
影响因子：
3.2
作者：
Huang,Chou-Long;Kuo,Elizabeth;Toto,RobertD
通讯作者：
Toto,RobertD