Fig. 7.

Diagrams depicting how PIP2 works in concert with Ca²⁺ and calmodulin (CaM) in the proposed activation mechanism of the SK2 channel. (A) The conformational state transition mechanism of the hSK2–CaM complex. (B) The widening of the SK2 intracellular gate through the disruption of the cross-subunit R395:E398 salt bridge by PIP2. (C) The movement of PIP2 into the SK2 activation site. (D) Depiction of the conveyor belt-like movement of PIP2 by binding to multiple basic residues in the CaMBD of SK2 channels.