SHAKER AND ETHER-A-GO-GO K+ CHANNEL SUBUNITS FAIL TO COASSEMBLE IN XENOPUS OOCYTES

Members of different voltage-gated K+ channel subfamilies usually do n ot form heteromultimers. However, coassembly between Shaker and ether- B-go-go (eag) subunits, members of two distinct K+ channel subfamilies , was suggested by genetic and functional studies (Zhong and Wu. 1991. Science. 252:1562-1564; Chen, M.-L., T. Hoshi, and C.-F. Wu. 1996. Ne uron. 17:535-542). We investigated whether Shaker and eag form heterom ultimers in Xenopus laevis oocytes using electrophysiological and bioc hemical approaches. Coexpression of Shaker and eag subunits produced K + currents that were virtually identical to the sum of separate Shaker and eag currents, with no change in the kinetics of Shaker inactivati on. According to the results of dominant negative and reciprocal coimm unoprecipitation experiments, the Shaker and eag proteins do not inter act. We conclude that Shaker and eag do not coassemble to form heterom ultimers in Xenopus oocytes.