Potassium channels in leukocytes and toxins that block them: Structure, function and therapeutic implications

Yet to appear in immunology text books, potassium channels are an important class of signaling molecules that play crucial roles in the physiology of leukocytes. By maintaining membrane potential, modulating calcium signaling or regulating cell volume, they tightly control leukocyte development and activation. The discovery of peptide toxins that selectively and potently b lock potassium channels has unraveled the functional relevance of these mem brane proteins in leukocyte signaling. In addition, these toxins have serve d as powerful tools in high-throughput screening and as molecular probes to study channel structure. This review summarizes the expression pattern, mo lecular determinants, physiological roles and therapeutic significance of p otassium channels in white blood cells and the peptide toxins that block th em.