KCa11

KCa11, also known as Maxi-K or BK channel, is a calcium-activated potassium channel. It is a large conductance channel that plays a significant role in regulating vascular tone, smooth muscle contraction, and neuronal excitability. The channel is characterized by its ability to conduct potassium ions and its activation by intracellular calcium ions and membrane voltage.

The KCa11 channel is a tetrameric protein formed by four alpha subunits. Each alpha subunit contains seven transmembrane segments and an intracellular C-terminal domain that binds to the beta regulatory subunits. These beta subunits modulate the channel's gating properties, including its sensitivity to calcium and voltage.

KCa11 channels are widely distributed in various tissues, including the cardiovascular system, nervous system, and smooth muscle. In the vasculature, they contribute to vasodilation by hyperpolarizing smooth muscle cells, reducing calcium influx and promoting relaxation. In neurons, KCa11 channels help regulate neuronal firing patterns and synaptic transmission.

Dysfunction of KCa11 channels has been implicated in several diseases, including hypertension, asthma, and epilepsy. Research into KCa11 channel modulators is ongoing, with potential therapeutic applications for these conditions. The channel's complex structure and diverse functions make it a compelling target for pharmacological intervention.