Channelopathy-causing mutations in the S₄₅A/S₄₅B and HA/HB helices of K_Ca2.3 and K_Ca3.1 channels alter their apparent Ca²⁺ sensitivity.

ABSTRACT: Small- and intermediate-conductance Ca²⁺-activated potassium (K_Ca2.x and K_Ca3.1, also called SK and IK) channels are activated exclusively by a Ca²⁺-calmodulin gating mechanism. Wild-type K_Ca2.3 channels have a Ca²⁺ EC₅₀ value of ∼0.3 μM, while the apparent Ca²⁺ sensitivity of wild-type K_Ca3.1 channels is ∼0.27 μM. Heterozygous genetic mutations of K_Ca2.3 channels have been associated with Zimmermann-Laband syndrome and idiopathic noncirrhotic portal hypertension, while K_Ca3.1 channel mutations were reported in hereditary xerocytosis patients. K_Ca2.3_S436C and K_Ca2.3_V450L channels with mutations in the S₄₅A/S₄₅B helices exhibi

SUBMITTER: Orfali R 

PROVIDER: S-EPMC8844225 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature