A discrete amino terminal domain of Kv1.5 and Kv1.4 potassium channels interacts with the spectrin repeats of alpha-actinin-2

The interaction between the amino terminus of Kv1-type potassium channels a nd alpha -actinin-2 has been investigated. Using a combination of yeast two -hybrid analysis and in vitro binding assays, alpha -actinin-2 was found to bind to the N-termini of both Kv1.4 and Kv1.5 but not to the equivalent se gments of Kv1.1, Kv1.2 or Kv1.3, Deletion analysis in the in vitro binding assays delineated the actinin binding region of Kv1.5 to between amino acid s 73 and 148 of the channel. The Kv1.5 binding sites in alpha -actinin-2 we re found to lie within actinin's internal spectrin repeats. Unlike the repo rted interaction between actinin and the NMDA receptor, calmodulin was foun d to have no effect on actinin binding to Kv1.5. (C) 2001 Published by Else vier Science B.V, on behalf of the Federation of European Biochemical Socie ties.