INTERACTION OF THE K CHANNEL BETA-SUBUNIT, HYPERKINETIC, WITH EAG FAMILY MEMBERS

Assembly of K channel alpha subunits of the Sharer (Sh) family occurs in a subfamily specific manner. It has been suggested that subfamily s pecificity also applies in the association of beta subunits with Sh ch annels (Rhodes, & J., Keilbaugh, S. A. Barrezueta, N. X. Lopez, K. L., and Trimmer, J, S, (1995) J. Neurosci. 15, 5360-5371; Sewing, S., Roe per, J. and Pongs, O. (1996) Neuron 16, 455-463; Yu, W., Xu, J., and L i, M. (1996) Neuron 16, 441-453). Here we show that the Drosophila bet a subunit homologue hyperkinetic (Elk) associates with members of the ether a go-go (eag), as well as Sh, families. Anti-BAG antibody coprec ipitates EAG and HK indicating a physical association between proteins . Heterologously expressed Hk dramatically increases the amplitudes of eag currents and also affects gating and modulation by progesterone. Through their ability to interact with a range of alpha subunits, the beta subunits of voltage-gated K channels are likely to have a much br oader impact on the signaling properties of neurons and muscle fibers than previously suggested.