Two structurally-unrelated regulatory proteins utilize parallel molecular mechanisms to selectively tune calcium and calmodulin feedback of calcium and sodium ion channels and reveals a novel strategy to engineer synthetic channel modulators.
Single and double-knockout mouse models for proteins associated with nodes of Ranvier reveal that a paranodal, spectrin-based lateral diffusion barrier is sufficient to cluster Na+ channels at nodes of Ranvier.
Determining how GIRK2 activity depends on the concentration of Gβγ subunits in lipid membranes at different Na+ concentrations has allowed the Gβγ concentration generated during GABAB activation in neurons to be estimated.
The G protein subunits Gβγ and the signaling lipid PIP2 are simultaneously needed to activate the potassium ion channel GIRK2 to control the voltage across a lipid bilayer, while sodium ions modulate these molecules' effects.
The GIRK1 subunit contains a defective Na+-binding site but behaves as if it is permanently bound to a sodium ion, and therefore increases the affinity of Gβγ to GIRK1/4 hetero-tetrameric channels in lipid membranes.
Transient Ca elevations of cytoplasmic calcium in cardiac myocytes profoundly activate cardiac Na/K pump activity in parallel with physical-chemical changes of the sarcolemma but without involvement of conventional signaling mechanisms.