Transfer of β subunit regulation from high to low voltage-gated Ca2+ channels

High voltage-activated Ca2+ channel expression and gating is controlled by their beta subunits. Although the sites of interaction are known at the atomic level, how beta modulates gating remains to be determined. Using a chimeric approach, beta subunit regulation was conferred to a low voltage-activated channel. Regulation was dependent on a rigid linker connecting the a, interaction domain to IS6. Chimeric channels also revealed a role for IS6 in channel gating. Taken together, these results support a direct coupling model where beta subunits alter movements in IS6 that occur as the channel transits between closed, open, and inactivated states. (c) 2005 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.