M-type K+ channels, encoded by KCNQ2-KCNQ5 genes, play key roles in regulation of neuronal excitability; however, less is known about the mechanisms controlling their transcriptional expression. Here, we discovered a mechanism regulating KCNQ2/3 transcriptional expression by neuronal activity in rodent neurons, involving activation of calcineurin and nuclear factor of activated T cell (NFAT) transcription factors, orchestrated by A kinase-anchoring protein (AKAP)79/150. The signal requires Ca2+ influx through L-type Ca2+ channels and both local and global Ca2+ elevations. We postulate increased M-channel expression to act as a negative feedback to suppress neuronal hyperexcitability, demonstrated by profoundly upregulated KCNQ2/3 transcription in hippocampi from wild-type, but not AKAP150-/-, mice after drug-induced seizures. Thus, we suggest a distinct role of AKAP79/150 and the complex it organizes in activity-dependent M-channel transcription, which may potentially serve throughout the nervous system to limit overexcitability associated with disease states such as epilepsy.
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