Intermediate conductance calcium-activated potassium channel protein 4 (KCa3.1) (KCa3.1)

The KCa3.1 calcium-activated potassium channel, also known as the intermediate conductance calcium-activated potassium channel or Gardos channel, is a voltage-independent ion channel primarily expressed in non-excitable cells, including hematopoietic cells, epithelia, and vascular endothelium [4, 6, 9]. It is activated by increases in intracellular calcium through a constitutive interaction with calmodulin, leading to potassium efflux and membrane hyperpolarization [1, 9]. This hyperpolarization maintains the electrical driving force for sustained calcium influx, which is critical for T-cell activation, cell proliferation, and migration [4, 8, 10]. In erythrocytes, KCa3.1 regulates cell volume, and its overactivation contributes to the dehydration of red blood cells in sickle cell disease [3, 12]. The channel is also significantly upregulated in various cancers, where it promotes tumor cell growth and metastasis, and in inflammatory diseases like asthma and rheumatoid arthritis [14, 16]. Consequently, KCa3.1 is a prominent therapeutic target, with pharmacological modulators such as the blocker Senicapoc being investigated for treating sickle cell anemia and inflammatory conditions [4, 16].

Other names

IK1SK4hIK1hSK4KCNN4Gardos channelIKCa1SMIKKCa4

KCa3.1 channel blockers inhibit potassium efflux, leading to membrane depolarization and reduced calcium signaling, which suppresses cell proliferation and immune activation. Conversely, KCa3.1 activators enhance potassium efflux and hyperpolarization, modulating vascular tone and neuronal excitability.