SEQUENCE AND FUNCTION OF THE 2 P DOMAIN POTASSIUM CHANNELS - IMPLICATIONS OF AN EMERGING SUPERFAMILY

A new superfamily of K+ channels has emerged in the past 2 years. Nota ble for possessing two pore-forming P domains in each subunit, members of the superfamily have been recognized through phylogeny from micro- organisms to humans. Four subfamilies of two P domain channels have be en isolated thus far; among these are the first cloned examples of out ward rectifier and open rectifier (or leak) K+ channels. The two P dom ain K+ channels offer a new perspective from which to glimpse the mole cular basis for function and dysfunction of K+-selective ion channels.