McKenzie FR, Connelly MA, Balzarano D, M?ller JR, Geleziunas R, Marcu KB. Functional isoforms of IkappaB kinase alpha (IKKalpha) lacking leucine zipper and helix-loop-helix domains reveal that IKKalpha and IKKbeta have different activation requirements. Mol Cell Biol. 2000 Apr; 20(8):2635-49.