K2P Channels Regulate Presynaptic Organisation through a Membrane Potential-Independent Mechanism
Neuronal ion channels have well-established effects on synaptic plasticity, in many cases by influencing pathways that depend on membrane excitability. Here we find that a C. elegans two-pore domain potassium (K2P) channel, TWK-40, regulates presynaptic organisation through a membrane potential-independent mechanism. Instead, this mechanism depends on TWK-40's effects on intracellular potassium…
Comprehensive research has unveiled a novel mechanism by which potassium channels impact presynaptic organization, independent of membrane potential. A specific potassium channel, TWK-40, in the microscopic worm C. elegans has been found to perform this function. Rather than affecting excitability, TWK-40's influence stems from its impact on intracellular potassium levels.
When TWK-40 malfunctions, it results in an overabundance of presynaptic proteins. Conversely, mutations that enhance its activity lead to a depletion of these proteins, causing disruptions in synaptic transmission. These abnormalities can be mirrored by mutations in transporter proteins that similarly alter intracellular potassium levels, but not by mutations in sodium channels, which affect membrane excitability instead.
The study suggests that an increase in cytoplasmic potassium encourages the assembly of presynaptic components. This process is dependent on the PYK-1 enzyme, a potassium-sensitive protein, and three transcription factors. These findings establish a new pathway, linking potassium homeostasis in neurons to the regulation of presynaptic organization and synaptic function.
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