Alterations of Nedd4-2-binding capacity in PY-motif of NaV 1.5 channel underlie long QT syndrome and Brugada syndrome
Alterations of Nedd4-2-binding capacity in PY-motif of NaV 1.5 channel underlie long QT syndrome and Brugada syndrome
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NaV 1.5 通道 PY 基序中 Nedd4-2 结合能力的改变是长 QT 综合征和 Brugada 综合征的基础
DOI：
10.1111/apha.13438
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
Tingzhong Wang
中科院分区：
文献类型：
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作者：
Ya Wang;Yuan Du;Ling Luo;Peijing Hu;Guodong Yang;Tao Li;Xiu Han;Aiqun Ma;Tingzhong Wang
目的SCN5A基因的致病变异可导致Brugada综合征(BRS)和长QT综合征(LQTS)，易导致潜在的致死性室性心律失常和心脏性猝死。SCN5A编码NaV1.5蛋白，该蛋白是电压依赖性心肌Na+通道的成孔α亚基。利用WW结构域，E3泛素连接酶Nedd4-2与NaV1.5 C末端的PY基序([L/P]Pxy)结合，导致蛋白表达下降，电流通过NaV1.5泛素化。在此，我们研究了E3泛素连接酶Nedd4-2介导的NaV1.5降解在BRS相关变异体SCN5A-p.L1239P和LQTS相关变异体SCN5A-p.Y1977N的病理机制中的作用。方法与结果采用分子生物学、生化和电生理相结合的方法，检测了SCN5A-p.L1239P和SCN5A-p.Y1977N的表达、功能和Nedd4-2的相互作用。SCN5A-p.L1239P的特征是功能丧失，而SCN5A-p.Y1977N是NaV1.5通道的功能增益变体。序列比对表明，BRS相关的SCN5A-p.L1239P有一个新的Nedd4-2结合位点(从LLxY到LPxY)。这个新的Nedd4-2结合位点增加了NaV1.5和Nedd4-2之间的相互作用，促进了NaV1.5通道的泛素化和降解。破坏SCN5A-p.L1239P新的Nedd4-2结合位点可恢复NaV1.5的表达和功能。然而，与LQTS相关的SCN5A-p.Y1977N破坏了通常的Nedd4-2结合位点(从PPxY到PPxN)。这减少了NaV1.5-Nedd4-2的相互作用，阻止了NaV1.5通道的泛素化和降解。结论PY基序通过Nedd4-2介导的泛素化在调节NaV1.5通道的表达/功能中发挥重要作用。NaV1.5-Nedd4-2相互作用的改变是SCN5A变异引起NaV1.5经络疾病的一种新的病理机制。
AimsPathogenic variants of the SCN5A gene can cause Brugada syndrome (BrS) and long QT syndrome (LQTS), which predispose individuals to potentially fatal ventricular arrhythmias and sudden cardiac death. SCN5A encodes the NaV1.5 protein, the pore forming α‐subunit of the voltage‐dependent cardiac Na+channel. Using a WW domain, the E3 ubiquitin ligase Nedd4‐2 binds to the PY‐motif ([L/P]PxY) within the C‐terminus of NaV1.5, which results in decreased protein expression and current through NaV1.5 ubiquitination. Here, we investigate the role of E3 ubiquitin ligase Nedd4‐2‐mediated NaV1.5 degradation in the pathological mechanisms of the BrS‐associated variant SCN5A‐p.L1239P and LQTS‐associated variant SCN5A‐p.Y1977N.Methods and ResultsUsing a combination of molecular biology, biochemical and electrophysiological approaches, we examined the expression, function and Nedd4‐2 interactions of SCN5A‐p.L1239P and SCN5A‐p.Y1977N. SCN5A‐p.L1239P is characterized as a loss‐of‐function, whereas SCN5A‐p.Y1977N is a gain‐of‐function variant of the NaV1.5 channel. Sequence alignment shows that BrS‐associated SCN5A‐p.L1239P has a new Nedd4‐2‐binding site (from LLxY to LPxY). This new Nedd4‐2‐binding site increases the interaction between NaV1.5 and Nedd4‐2, enhancing ubiquitination and degradation of the NaV1.5 channel. Disruption of the new Nedd4‐2‐binding site of SCN5A‐p.L1239P restores NaV1.5 expression and function. However, the LQTS‐associated SCN5A‐p.Y1977N disrupts the usual Nedd4‐2‐binding site (from PPxY to PPxN). This decreases NaV1.5‐Nedd4‐2 interaction, preventing ubiquitination and degradation of NaV1.5 channels.ConclusionsOur data suggest that the PY‐motif plays an essential role in modifying the expression/function of NaV1.5 channels through Nedd4‐2‐mediated ubiquitination. Alterations of NaV1.5‐Nedd4‐2 interaction represent a novel pathological mechanism for NaV1.5 channel diseases caused by SCN5A variants.