KCR1, A MEMBRANE-PROTEIN THAT FACILITATES FUNCTIONAL EXPRESSION OF NONINACTIVATING K-DEPENDENT K+ CHANNELS( CURRENTS ASSOCIATES WITH RAT EAG VOLTAGE)

Cerebellar granule neurons possess a non-inactivating K+ current, whic h controls resting membrane potentials and modulates the firing rate b y means of muscarinic agonists. kcr1 was cloned from the cerebellar cD NA library by suppression cloning. KCR1 is a novel protein with 12 put ative transmembrane domains and enhances the functional expression of the cerebellar non-inactivating K+ current in Xenopus oocytes, KCR1 al so accelerates the activation of rat EAG K+ channels expressed in Xeno pus oocytes or in COS-7 cells. Far-Western blotting revealed that KCR1 and EAG proteins interacted with each other by means of their C-termi nal regions. These results suggest that KCR1 is the regulatory compone nt of non-inactivating K+ channels.