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Extracellular Kir2.1C122Y Mutant Upsets Kir2.1-PIP2 Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome

Fecha de publicación:

Autores de IIS La Fe

Participantes ajenos a IIS La Fe

  • Cruz, FM
  • Macias, A
  • Moreno-Manuel, AI
  • Gutiérrez, LK
  • Vera-Pedrosa, ML
  • Martínez-Carrascoso, I
  • Pérez, PS
  • Robles, JMR
  • Bermúdez-Jiménez, FJ
  • Díaz-Agustin, A
  • de Benito, FM
  • Arias-Santiago, S
  • Martin-Martínez, M
  • Gutierrez-Rodriguez, M
  • Bernal, JA
  • Jiménez-Jaimez, J
  • Jalife, J

Grupos

Abstract

BACKGROUND: Andersen-Tawil syndrome type 1 is a rare heritable disease caused by mutations in the gene coding the strong inwardly rectifying K+ channel Kir2.1. The extracellular Cys (cysteine)(122)-to-Cys(154) disulfide bond in the channel structure is crucial for proper folding but has not been associated with correct channel function at the membrane. We evaluated whether a human mutation at the Cys(122)-to-Cys(154) disulfide bridge leads to Kir2.1 channel dysfunction and arrhythmias by reorganizing the overall Kir2.1 channel structure and destabilizing its open state. METHODS: We identified a Kir2.1 loss-of-function mutation (c.366 A>T; p.Cys122Tyr) in an ATS1 family. To investigate its pathophysiological implications, we generated an AAV9-mediated cardiac-specific mouse model expressing the Kir2.1(C122Y) variant. We employed a multidisciplinary approach, integrating patch clamping and intracardiac stimulation, molecular biology techniques, molecular dynamics, and bioluminescence resonance energy transfer experiments. RESULTS: Kir2.1(C122Y) mice recapitulated the ECG features of ATS1 independently of sex, including corrected QT prolongation, conduction defects, and increased arrhythmia susceptibility. Isolated Kir2.1(C122Y) cardiomyocytes showed significantly reduced inwardly rectifier K+ (I-K1) and inward Na+ (I-Na) current densities independently of normal trafficking. Molecular dynamics predicted that the C122Y mutation provoked a conformational change over the 2000-ns simulation, characterized by a greater loss of hydrogen bonds between Kir2.1 and phosphatidylinositol 4,5-bisphosphate than wild type (WT). Therefore, the phosphatidylinositol 4,5-bisphosphate-binding pocket was destabilized, resulting in a lower conductance state compared with WT. Accordingly, on inside-out patch clamping, the C122Y mutation significantly blunted Kir2.1 sensitivity to increasing phosphatidylinositol 4,5-bisphosphate concentrations. In addition, the Kir2.1(C122Y) mutation resulted in channelosome degradation, demonstrating temporal instability of both Kir2.1 and Na(V)1.5 proteins. CONCLUSIONS: The extracellular Cys(122)-to-Cys(154) disulfide bond in the tridimensional Kir2.1 channel structure is essential for the channel function. We demonstrate that breaking disulfide bonds in the extracellular domain disrupts phosphatidylinositol 4,5-bisphosphate-dependent regulation, leading to channel dysfunction and defects in Kir2.1 energetic stability. The mutation also alters functional expression of the Na(V)1.5 channel and ultimately leads to conduction disturbances and life-threatening arrhythmia characteristic of Andersen-Tawil syndrome type 1.

Datos de la publicación

ISSN/ISSNe:
0009-7330, 1524-4571

CIRCULATION RESEARCH  LIPPINCOTT WILLIAMS & WILKINS

Tipo:
Article
Páginas:
52-71
PubMed:
38497220
Factor de Impacto:
4,709 SCImago ℠
Cuartil:
Q1 SCImago ℠

Citas Recibidas en Web of Science: 8

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Keywords

  • andersen syndrome; arrhythmias, cardiac; death, sudden, cardiac; membrane potentials; organisms, genetically modified; tachycardia, ventricular; ventricular fibrillation

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