Epilepsy channelopathies go neddy: Stabilizing NaV1.1 channels by neddylation

Abstract

Loss-of-function mutations of SCN1A encoding the pore-forming α subunit of the NaV1.1 neuronal sodium channel cause a severe developmental epileptic encephalopathy, Dravet syndrome (DS). In this issue of the JCI, Chen, Luo, Gao, et al. describe a phenocopy for DS in mice deficient for posttranslational conjugation with neural precursor cell expressed, developmentally downregulated 8 (NEDD8) (neddylation), selectively engineered in inhibitory interneurons. Pursuing the possibility that this phenotype is also caused by loss of NaV1.1, Chen, Luo, Gao, and colleagues show that interneuron excitability and GABA release are impaired, NaV1.1 degradation rate is increased with a commensurate decrease of NaV1.1 protein, and NaV1.1 is a substrate for neddylation. These findings establish neddylation as a mechanism for stabilizing NaV1.1 subunits and suggest another pathomechanism for epileptic sodium channelopathy.