Phylogeny of ion channels: clues to structure and function

Voltage-gated ion channels are responsible for the electrical activity in a variety of cell types in modern-day animals, However, they represent the r esult of many millions of years of evolution of a family of ion channel pro teins that are also found in prokaryotes and diverse eukaryotes, and probab ly exist in all life forms. This review traces the evolution of ion channel s, with particular emphasis on the factors and evolutionary pathways that m ay have given rise to voltage-gated potassium (K+), calcium (Ca2+), and sod ium (Na+) channels. The review also highlights the utility of comparing phy logenetically distinct versions of the same protein as a means to better un derstand the structure and function of proteins. (C) 2001 Elsevier Science Inc. All rights reserved.