Cullin 3 mutant causing familial hyperkalemic hypertension lacks normal activity in the kidney.
Cullin 3 mutant causing familial hyperkalemic hypertension lacks normal activity in the kidney.
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Cullin 3 突变体导致家族性高钾性高血压，肾脏缺乏正常活动。
DOI：
10.1152/ajprenal.00153.2022
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
McCormick,JamesA
中科院分区：
文献类型：
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作者：
Maeoka,Yujiro;Cornelius,RyanJ;Ferdaus,MohammedZubaerul;Sharma,Avika;Nguyen,LuanT;McCormick,JamesA
泛素连接酶支架蛋白cullin 3(CUL3)突变导致家族性高钾性高血压(FHHt)。我们最近报道，在肾脏中，突变的CUL3(CUL3-Δ9)活性降低了CUL3-Δ9和Kelch样3的丰度，Kelch样3是CUL3底物与非赖氨酸激酶4(WNK4)的适配器，这在机制上具有重要意义。然而，CUL3-Δ9是否对其他可能改变肾功能的靶点产生额外影响尚不清楚。在这里，我们试图确定1)CUL3-Δ9的表达是否可以挽救肾小管特异性基因敲除小鼠的表型，以及2)CUL3-Δ9的表达是否影响其他CUL3底物。使用可诱导的肾小管特异性系统，我们研究了两种表达CUL3-Δ9的小鼠模型：CUL3基因敲除(CUL3-/-/Δ9)和CUL3杂合背景(CUL3+/-/Δ9，FHHt模型)。以Cu3-/-和Cu3+/-小鼠为对照，比较了Cu3-Δ9对这些小鼠的作用。与CUL3-/-小鼠相似，CUL3-/-/Δ9小鼠表现为多尿，水通道蛋白2丢失，集合管损伤，近端小管也有损伤。CUL3-Δ9不促进积聚在CUL3/肾中的两个CUL3靶标的降解：高分子量细胞周期蛋白E和NAD(P)H：苯醌氧化还原酶1(NQO1)[CUL3-Kelch样ECH相关蛋白1(KEAP1)底物红系相关因子相关因子2的替代品]。由于CUL3-Δ9的表达不能挽救CUL3-/-表型，我们的数据提示CUL3-Δ9不能在泛素连接酶复合体中正常发挥作用。在Cu3+/-/Δ9小鼠中，Keap1的丰度没有变化，但NQO1的丰度更高，这表明CUL3-Δ9在体内对接头进行了隔离。综上所述，我们的结果提供了证据，证明在肾脏中，CUL3-Δ9完全缺乏正常的活性，并能将CUL3底物接头捕获在非活性复合体中。NEW&NOTEWORTHYCUL3突变(CUL3-Δ9)通过减少接头KLHL3，损害底物WNK4的降解，导致家族性高血钾高血压(FHHt)。目前尚不清楚CUL3-Δ9是否会影响肾脏的其他靶点。我们发现CUL3-Δ9不能降解Cyclin E和核因子红系相关因子2(NRF2；使用替代标记NQO1)这两个CUL3靶标，也不能解救由Cul3中断引起的损伤或多尿。在FHHt模型中，CUL3-Δ9在不减少其接头Keap1的情况下削弱了NRF2的降解。我们的数据为CUL3-Δ9在肾脏中的功能提供了更多的见解。
Mutations in the ubiquitin ligase scaffold protein cullin 3 (CUL3) cause the disease familial hyperkalemic hypertension (FHHt). We recently reported that in the kidney, aberrant mutant CUL3 (CUL3-Δ9) activity lowers the abundance of CUL3-Δ9 and Kelch-like 3, the CUL3 substrate adaptor for with-no-lysine kinase 4 (WNK4) and that this is mechanistically important. However, whether CUL3-Δ9 exerts additional effects on other targets that may alter renal function is unclear. Here, we sought to determine1) whether CUL3-Δ9 expression can rescue the phenotype of renal tubule-specificCul3knockout mice, and2) whether CUL3-Δ9 expression affects other CUL3 substrates. Using an inducible renal tubule-specific system, we studied two CUL3-Δ9-expressing mouse models:Cul3knockout (Cul3–/–/Δ9) andCul3heterozygous background (Cul3+/–/Δ9, FHHt model). The effects of CUL3-Δ9 in these mice were compared withCul3–/–andCul3+/–mice. Similar toCul3–/–mice,Cul3–/–/Δ9mice displayed polyuria with loss of aquaporin 2 and collecting duct injury; proximal tubule injury also occurred. CUL3-Δ9 did not promote degradation of two CUL3 targets that accumulate in theCul3–/–kidney: high-molecular-weight (HMW) cyclin E and NAD(P)H:quinone oxidoreductase 1 (NQO1) [a surrogate for the CUL3-Kelch-like ECH-associated protein 1 (KEAP1) substrate nuclear factor erythroid-2-related factor 2]. Since CUL3-Δ9 expression cannot rescue theCul3–/–phenotype, our data suggest that CUL3-Δ9 cannot normally function in ubiquitin ligase complexes. InCul3+/–/Δ9mice, KEAP1 abundance did not differ but NQO1 abundance was higher, suggesting adaptor sequestration by CUL3-Δ9 in vivo. Together, our results provide evidence that in the kidney, CUL3-Δ9 completely lacks normal activity and can trap CUL3 substrate adaptors in inactive complexes.NEW & NOTEWORTHYCUL3 mutation (CUL3-Δ9) causes familial hyperkalemic hypertension (FHHt) by reducing adaptor KLHL3, impairing substrate WNK4 degradation. Whether CUL3-Δ9 affects other targets in kidneys remains unclear. We found that CUL3-Δ9 cannot degrade two CUL3 targets, cyclin E and nuclear factor erythroid-2-related factor 2 (NRF2; using a surrogate marker NQO1), or rescue injury or polyuria caused byCul3disruption. In an FHHt model, CUL3-Δ9 impaired NRF2 degradation without reduction of its adaptor KEAP1. Our data provide additional insights into CUL3-Δ9 function in the kidney.