Small conductance calcium-activated potassium channel protein 1 (KCa2.1) (KCa2.1)

KCa2.1, also known as Small conductance calcium-activated potassium channel protein 1 (SK1), is a voltage-independent potassium channel that is gated by intracellular calcium ions [1, 5]. It functions as a heterotetramer or homotetramer, with each subunit constitutively bound to calmodulin, which acts as the calcium sensor [1, 5, 14]. KCa2.1 is primarily expressed in the central nervous system and the heart, where it plays a vital role in regulating cellular excitability by contributing to the medium afterhyperpolarization (mAHP) following an action potential [1, 6, 18]. In neurons, this activity helps control firing frequency and synaptic plasticity, making it a target for neurodegenerative diseases and neuropathic pain [2, 8, 11]. In the heart, KCa2.1 is predominantly found in the atria and is involved in the repolarization of the cardiac action potential, with its dysregulation linked to atrial fibrillation [18, 19]. Pharmacological agents such as the bee venom peptide apamin act as blockers, while small molecules like GW542573X and riluzole serve as activators or positive gating modulators to fine-tune channel activity for therapeutic purposes [4, 7, 8].

Other names

SK1KCNN1hSK1SKCa1Potassium calcium-activated channel subfamily N member 1

Channel blocker, Positive gating modulator, Negative gating modulator