Sodium-activated potassium channel subunit KNa1.1 (KCNT1)

The Slack potassium channel (KCNT1, KNa1.1, Slo2.2) is a large, sodium-activated potassium channel highly expressed in neurons throughout the brain. Its structure includes six transmembrane domains per subunit and a very large cytoplasmic C-terminal tail containing two regulator of conductance of potassium (RCK) domains. Slack channels are crucial for modulating neuronal action potential firing, burst firing, and overall membrane excitability. They are distinct from classical voltage-gated potassium channels: Slack channels are activated by intracellular sodium rather than changes in voltage, and they are insensitive to calcium. Pathogenic variants in KCNT1 are associated with early-onset epileptic syndromes and intellectual disability, underlining their significance in higher brain functions and neurodevelopmental disease. Experimentally, Slack channels interact with proteins such as Fragile X mental retardation protein, suggesting a role in diseases like Fragile X syndrome and autism. Therapeutic strategies are emerging, focusing on channel inhibition or knockdown using antisense technologies, but selective, safe drugs remain a challenge due to the risk of off-target effects and adverse cardiac outcomes.

Other names

SlackSlo2.2KCNT1KNa1.1sodium-activated potassium channel

Channel inhibition (by molecules such as quinidine, blocking excessive channel activity caused by gain-of-function mutations) Reduction of KCNT1 expression (via antisense oligonucleotides)