Voltage-Gated Sodium Channel Na_V1.2: Structural Perspective of the Genetic Variability

The SCN2A gene encodes the alpha subunit of a voltage-gated sodium channel which is necessary for creating and propagating action potentials in neurons. Impairment of the Na_v1.2 function is associated with neurodevelopmental disorders such as Developmental and Epileptic Encephalopathy, Self-limited Neonatal/Infantile Seizures, and Autism Spectrum Disorder. In this study, we used orthologous sequence comparisons, as well as disease associated variants to analyze their location in the structure of Na_v1.2, with the aim of understanding the impact of genetic variants in the structure of this protein at an evolutionary and clinical level. Our analyses reveal different spatial distribution of interspecific variation where different residues locate preferentially in the first cytoplasmic linker, while disease-associated variants tend to cluster in the voltage-sensing segments of the protein domains. Altogether, these discoveries point to structurally important segments in the Na_v1.2 structure that have been conserved through evolution due to their role in maintaining the function of the channel.