Epilepsy-linked kinase CDKL5 phosphorylates voltage-gated calcium channel Cav2.3, altering inactivation kinetics and neuronal excitability

Developmental and epileptic encephalopathies (DEEs) are a group of rare childhood disorders characterized by severe epilepsy and cognitive deficits. Numerous DEE genes have been discovered thanks to advances in genomic diagnosis, yet putative molecular links between these disorders are unknown. CDKL...

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Published inbioRxiv
Main Authors Sampedro-Castaneda, Marisol, Baltussen, Lucas L, Lopes, Andre T, Qiu, Yichen, Sirvio, Liina, Mihaylov, Simeon R, Claxton, Suzanne, Richardson, Jill C, Lignani, Gabriele, Ultanir, Sila K
Format Paper
LanguageEnglish
Published Cold Spring Harbor Cold Spring Harbor Laboratory Press 08.02.2023
Subjects
Calcium channels (voltage-gated)
Channel gating
Channelopathy
Children
Cognitive ability
Electrophysiology
Epilepsy
Excitability
Kinetics
Mutation
Phosphorylation
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Summary:Developmental and epileptic encephalopathies (DEEs) are a group of rare childhood disorders characterized by severe epilepsy and cognitive deficits. Numerous DEE genes have been discovered thanks to advances in genomic diagnosis, yet putative molecular links between these disorders are unknown. CDKL5 deficiency disorder (CDD, DEE2), one of the most common genetic epilepsies, is caused by loss-of-function mutations in the brain-enriched kinase CDKL5. To elucidate CDKL5 function, we looked for CDKL5 substrates using a SILAC-based phosphoproteomic screen. We identified the voltage-gated Ca2+ channel Cav2.3 (encoded by CACNA1E) as a novel physiological target of CDKL5 in mice and humans. Recombinant channel electrophysiology and interdisciplinary characterization of Cav2.3 phosphomutant mice revealed that loss of Cav2.3 phosphorylation leads to channel gain-of-function via slower inactivation and enhanced cholinergic stimulation, resulting in increased neuronal excitability. Our results thus show that CDD is partly a channelopathy. The properties of unphosphorylated Cav2.3 closely resemble those described for CACNA1E gain-of-function mutations causing DEE69, a disorder sharing clinical features with CDD. We show that these two single-gene diseases are mechanistically related and could be ameliorated with Cav2.3 inhibitors.Competing Interest StatementThe authors have declared no competing interest.Footnotes* Small edits to Abstract, last section of the Discussion and Figure Legends 1 Author affiliation updated
DOI:10.1101/2022.11.24.517538