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Clatot J, Currin CB, Liang Q, Pipatpolkai T, Massey SL, Helbig I, Delemotte L, Vogels TP, Covarrubias M, Goldberg EM. A structurally precise mechanism links an epilepsy-associated KCNC2 potassium channel mutation to interneuron dysfunction. Proc Natl Acad Sci U S A 2024; 121:e2307776121. [PMID: 38194456 PMCID: PMC10801864 DOI: 10.1073/pnas.2307776121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 11/17/2023] [Indexed: 01/11/2024] Open
Abstract
De novo heterozygous variants in KCNC2 encoding the voltage-gated potassium (K+) channel subunit Kv3.2 are a recently described cause of developmental and epileptic encephalopathy (DEE). A de novo variant in KCNC2 c.374G > A (p.Cys125Tyr) was identified via exome sequencing in a patient with DEE. Relative to wild-type Kv3.2, Kv3.2-p.Cys125Tyr induces K+ currents exhibiting a large hyperpolarizing shift in the voltage dependence of activation, accelerated activation, and delayed deactivation consistent with a relative stabilization of the open conformation, along with increased current density. Leveraging the cryogenic electron microscopy (cryo-EM) structure of Kv3.1, molecular dynamic simulations suggest that a strong π-π stacking interaction between the variant Tyr125 and Tyr156 in the α-6 helix of the T1 domain promotes a relative stabilization of the open conformation of the channel, which underlies the observed gain of function. A multicompartment computational model of a Kv3-expressing parvalbumin-positive cerebral cortex fast-spiking γ-aminobutyric acidergic (GABAergic) interneuron (PV-IN) demonstrates how the Kv3.2-Cys125Tyr variant impairs neuronal excitability and dysregulates inhibition in cerebral cortex circuits to explain the resulting epilepsy.
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Affiliation(s)
- Jerome Clatot
- Division of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA19104
- The Epilepsy Neurogenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia,PA19104
| | | | - Qiansheng Liang
- Department of Neuroscience and Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA19107
| | - Tanadet Pipatpolkai
- Department of Applied Physics, Science for Life Laboratory, Royal Institute of Technology, SolnaSE-171 21, Sweden
| | - Shavonne L. Massey
- Division of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA19104
- The Epilepsy Neurogenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia,PA19104
- The Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA19104
| | - Ingo Helbig
- Division of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA19104
- The Epilepsy Neurogenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia,PA19104
- The Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA19104
- Department of Biomedical and Health Informatics, The Children’s Hospital of Philadelphia, Philadelphia, PA19104
| | - Lucie Delemotte
- Department of Applied Physics, Science for Life Laboratory, Royal Institute of Technology, SolnaSE-171 21, Sweden
| | - Tim P. Vogels
- The Institute of Science and Technology Austria, Klosterneuburg3400, Austria
| | - Manuel Covarrubias
- Department of Neuroscience and Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA19107
| | - Ethan M. Goldberg
- Division of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA19104
- The Epilepsy Neurogenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia,PA19104
- The Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA19104
- The Department of Neuroscience, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA19104
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