The movement of ions across cell membranes is essential for a wide variety of fundamental
physiological processes, including secretion, muscle contraction, and neuronal excitation.
This movement is possible because of the presence in the cell membrane of a class of
integral membrane proteins dubbed ion channels. Ion channels, thanks to the presence of
aqueous pores in their structure, catalyze the passage of ions across the otherwise ion-
impermeable lipid bilayer. Ion conduction across ion channels is highly regulated, and in the …