Elucidating the underlying molecular pathogenesis of NR3C2 mutants causing autosomal dominant pseudohypoaldosteronism type 1
Elucidating the underlying molecular pathogenesis of NR3C2 mutants causing autosomal dominant pseudohypoaldosteronism type 1
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DOI：
10.1210/jc.2006-1161
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发表时间：
2006-11-01
影响因子：
5.8
通讯作者：
Krone, Nils
中科院分区：
文献类型：
--
作者：
Riepe, Felix G.;Finkeldei, Johannes;Krone, Nils
背景：假性醛固酮减少症1型（PHA1）是一种罕见的嗜盐综合征。盐皮质激素受体（MR）NR3C2基因突变导致常染色体显性PHA1。目的：我们的目的是揭示6例PHA1患者肾盐丢失的原因，并分析突变对MR功能的影响。患者表型的临床和激素表征，NR3C2基因的分析，测定受体对醛固酮的亲和力和MR突变体的转录激活能力，使用荧光标记的MR研究亚细胞易位，并通过蛋白水解实验和三维建模研究突变体受体构象的变化。检测到6个杂合子NR3C2突变。以前曾报道过一个移码突变（c.1131dupT）。第二个移码突变（c.2871dupC），这是最近才被我们的小组报告，没有醛固酮结合，没有反式激活，因为受体构象的重大变化。两个新的无义突变产生截短的受体蛋白。两种错义突变不同地影响MR功能。S818L是最近报道的，没有完整的体外数据。S818L不结合醛固酮或激活转录或易位到细胞核中。参与醛固酮结合的几个残基的主要置换是PHA 1引起的。新的E972G突变表现出显着较低的配体结合亲和力，只有9%的野生型转录活性所造成的主要变化receptor conformation.Conclusions：我们的数据上的6个突变扩展了PHA1引起的NR3C2基因突变的光谱。研究自然发生的突变体有助于阐明它们的致病性，并确定MR结构和功能的关键残基。
Context: Pseudohypoaldosteronism type 1 (PHA1) is a rare saltwasting syndrome. Mutations in the NR3C2 gene coding for the mineralocorticoid receptor (MR) cause autosomal dominant PHA1.Objective: Our objective was to reveal the cause of renal salt loss in six PHA1 patients and analyze the mutants' functional impact on MR function.Design: Our study included the following: clinical and hormonal characterization of the patients' phenotype, analysis of the NR3C2 gene, determination of receptor affinities to aldosterone and the transcriptional activation abilities of the MR mutants, investigation of subcellular translocation using fluorescence-labeled MR, and studying changes in mutant receptor conformation with proteolysis experiments and three-dimensional modeling.Results: Six heterozygous NR3C2 mutations were detected. One frameshift mutation (c.1131dupT) has been reported previously. The second frameshift mutation (c.2871dupC), which has only recently been reported by our group, showed no aldosterone binding and no transactivation because of a major change in receptor conformation. Two novel nonsense mutations generate a truncated receptor protein. Two missense mutations differently affect MR function. S818L was reported recently without complete in vitro data. S818L does not bind aldosterone or activate transcription or translocate into the nucleus. A major displacement of several residues involved in aldosterone binding was PHA1 causing. The novel E972G mutation showed a significantly lower ligand-binding affinity and only 9% of wild-type transcriptional activity caused by major changes in receptor conformation.Conclusions: Our data on six mutations extend the spectrum of PHA1-causing NR3C2 gene mutations. Studying naturally occurring mutants helps to clarify their pathogenicity and to identify crucial residues for MR structure and function.