What are ion channels?

What are ion channels?

Definition
Ion channels are transmembrane pores which allow the passage of ions (charged particles) into and out of a cell down the electrochemical gradient. There are hundreds of different ion channels and they are distinguished based upon their ion selectivity, gating mechanism, and sequence similarity. Ion channels can be voltage-gated, ligand-gated, pH-gated, or mechanically gated. These gating criteria along with a combination of sequence similarity and ion selectivity further subdivides ion channels into several subtypes:

Browse ion channel database which includes all known ion channel genes/proteins discovered to-date. The database is arranged in a hierarchal format based upon gene ontology.