Aberrant activation or inhibition of potassium (K+) currents across the plasma membrane of cells has been causally linked to altered neurotransmission, cardiac arrhythmias, endocrine dysfunction, and (more rarely) perturbed developmental processes. The K+ channel subfamily K member 4 (KCNK4), also known as TRAAK (TWIK-related arachidonic acid-stimulated K+ channel), belongs to the mechano-gated ion channels of the TRAAK/TREK subfamily of two-pore-domain (K2P) K+ channels. While K2P channels are well known to contribute to the resting membrane potential and cellular excitability, their involvement in pathophysiological processes remains largely uncharacterized. We report that de novo missense mutations in KCNK4 cause a recognizable syndrome with a distinctive facial gestalt, for which we propose the acronym FHEIG (facial dysmorphism, hypertrichosis, epilepsy, intellectual disability/developmental delay, and gingival overgrowth). Patch-clamp analyses documented a significant gain of function of the identified KCNK4 channel mutants basally and impaired sensitivity to mechanical stimulation and arachidonic acid. Co-expression experiments indicated a dominant behavior of the disease-causing mutations. Molecular dynamics simulations consistently indicated that mutations favor sealing of the lateral intramembrane fenestration that has been proposed to negatively control K+ flow by allowing lipid access to the central cavity of the channel. Overall, our findings illustrate the pleiotropic effect of dysregulated KCNK4 function and provide support to the hypothesis of a gating mechanism based on the lateral fenestrations of K2P channels.

Mutations in KCNK4 that Affect Gating Cause a Recognizable Neurodevelopmental Syndrome / Bauer, Christiane K.; Calligari, Paolo; Radio, Francesca Clementina; Caputo, Viviana; Dentici, Maria Lisa; Falah, Nadia; High, Frances; Pantaleoni, Francesca; Barresi, Sabina; Ciolfi, Andrea; Pizzi, Simone; Bruselles, Alessandro; Person, Richard; Richards, Sarah; Cho, Megan T.; Claps Sepulveda, Daniela J.; Pro, Stefano; Battini, Roberta; Zampino, Giuseppe; Digilio, Maria Cristina; Bocchinfuso, Gianfranco; Dallapiccola, Bruno; Stella, Lorenzo; Tartaglia, Marco. - In: AMERICAN JOURNAL OF HUMAN GENETICS. - ISSN 0002-9297. - 103:4(2018), pp. 621-630. [10.1016/j.ajhg.2018.09.001]

Mutations in KCNK4 that Affect Gating Cause a Recognizable Neurodevelopmental Syndrome

Calligari, Paolo;Radio, Francesca Clementina;Caputo, Viviana;Dentici, Maria Lisa;Ciolfi, Andrea;Pizzi, Simone;Pro, Stefano;
2018

Abstract

Aberrant activation or inhibition of potassium (K+) currents across the plasma membrane of cells has been causally linked to altered neurotransmission, cardiac arrhythmias, endocrine dysfunction, and (more rarely) perturbed developmental processes. The K+ channel subfamily K member 4 (KCNK4), also known as TRAAK (TWIK-related arachidonic acid-stimulated K+ channel), belongs to the mechano-gated ion channels of the TRAAK/TREK subfamily of two-pore-domain (K2P) K+ channels. While K2P channels are well known to contribute to the resting membrane potential and cellular excitability, their involvement in pathophysiological processes remains largely uncharacterized. We report that de novo missense mutations in KCNK4 cause a recognizable syndrome with a distinctive facial gestalt, for which we propose the acronym FHEIG (facial dysmorphism, hypertrichosis, epilepsy, intellectual disability/developmental delay, and gingival overgrowth). Patch-clamp analyses documented a significant gain of function of the identified KCNK4 channel mutants basally and impaired sensitivity to mechanical stimulation and arachidonic acid. Co-expression experiments indicated a dominant behavior of the disease-causing mutations. Molecular dynamics simulations consistently indicated that mutations favor sealing of the lateral intramembrane fenestration that has been proposed to negatively control K+ flow by allowing lipid access to the central cavity of the channel. Overall, our findings illustrate the pleiotropic effect of dysregulated KCNK4 function and provide support to the hypothesis of a gating mechanism based on the lateral fenestrations of K2P channels.
2018
channelopathy; epilepsy; FHEIG syndrome; gingival overgrowth; hypertrichosis; intellectual disability; K2P channels; neurodevelopmental disorder; TRAAK; Genetics; Genetics (clinical)
01 Pubblicazione su rivista::01a Articolo in rivista
Mutations in KCNK4 that Affect Gating Cause a Recognizable Neurodevelopmental Syndrome / Bauer, Christiane K.; Calligari, Paolo; Radio, Francesca Clementina; Caputo, Viviana; Dentici, Maria Lisa; Falah, Nadia; High, Frances; Pantaleoni, Francesca; Barresi, Sabina; Ciolfi, Andrea; Pizzi, Simone; Bruselles, Alessandro; Person, Richard; Richards, Sarah; Cho, Megan T.; Claps Sepulveda, Daniela J.; Pro, Stefano; Battini, Roberta; Zampino, Giuseppe; Digilio, Maria Cristina; Bocchinfuso, Gianfranco; Dallapiccola, Bruno; Stella, Lorenzo; Tartaglia, Marco. - In: AMERICAN JOURNAL OF HUMAN GENETICS. - ISSN 0002-9297. - 103:4(2018), pp. 621-630. [10.1016/j.ajhg.2018.09.001]
File allegati a questo prodotto
File Dimensione Formato  
Bauer_NeurodevelopmentalSyndrome_2018.pdf

accesso aperto

Tipologia: Versione editoriale (versione pubblicata con il layout dell'editore)
Licenza: Creative commons
Dimensione 2.17 MB
Formato Adobe PDF
2.17 MB Adobe PDF

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1179916
Citazioni
  • ???jsp.display-item.citation.pmc??? 35
  • Scopus 70
  • ???jsp.display-item.citation.isi??? 67
social impact