Calcium dependence of both lobes of calmodulin is involved in binding to a cytoplasmic domain of SK channels.

ABSTRACT: KCa2.1-3 Ca²⁺-activated K⁺-channels (SK) require calmodulin to gate in response to cellular Ca²⁺. A model for SK gating proposes that the N-terminal domain (N-lobe) of calmodulin is required for activation, but an immobile C-terminal domain (C-lobe) has constitutive, Ca²⁺-independent binding. Although structures support a domain-driven hypothesis of SK gate activation by calmodulin, only a partial understanding is possible without measuring both channel activity and protein binding. We measured SK2 (KCa2.2) activity using inside-out patch recordings. Currents from calmodulin-disrupted SK2 channels can be restored with exogenously applied calmodulin. We find that SK2 activity only approaches full activation with full-length calmodulin with both an

SUBMITTER: Halling DB 

PROVIDER: S-EPMC9803350 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature