The phosphatidyl-inositol-4,5-bisphosphate (PIP 2) lipid has been shown to be crucial for the coupling between the voltage sensor and the pore of the potassium voltage-gated K V 7 channel family, especially the K V 7.1 channel. Expressed in the myocardium membrane, K V 7.1 forms a complex with KCNE1 auxiliary subunits to generate the I KS current. Here we present molecular models of the transmembrane region of this complex in its three known states, namely the Resting/Closed (RC), the Intermediate/Closed (IC), and the Activated/Open (AO), robustness of which is assessed by agreement with a range of biophysical data. Molecular Dynamics (MD) simulations of these models embedded in a lipid bilayer including phosphatidyl-inositol-4,5-bisphosphate (PIP 2) lipids show that in presence of KCNE1, two PIP 2 lipids are necessary to stabilize each state. The simulations also show that KCNE1 interacts with both PIP 2 binding sites, forming a tourniquet around the pore and preventing its opening. The present investigation provides therefore key molecular elements that govern the role of PIP 2 in KCNE1 modulation of I KS channels, possibly a common mechanism by which auxiliary KCNE subunits might modulate a variety of other ion channels.