Title: Transplantable sites confer calcium sensitivity to BK channels.

Authors: M Schreiber, A Yuan, L Salkoff

Journal, date & volume: Nat. Neurosci., 1999 May , 2, 416-21

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/10321244

Abstract
Both intracellular calcium and voltage activate Slo1, a high-conductance potassium channel, linking calcium with electrical excitability. Using molecular techniques, we created a calcium-insensitive variant of this channel gated by voltage alone. Calcium sensitivity was restored by adding back small portions of the carboxyl (C)-terminal 'tail' domain. Two separate regions of the tail independently conferred different degrees of calcium sensitivity; together, they restored essentially wild-type calcium dependence. These results suggest that, in the absence of calcium, the Slo1 tail inhibits voltage-dependent gating, and that calcium removes this inhibition. Slo1 may have evolved from an ancestral voltage-sensitive potassium channel represented by the core; the tail may represent the more recent addition of a calcium-dependent modulatory domain.