Fig 1.

Kch1 and Kch2 regulate HACS activation in response to α-factor mating pheromone. ⁴⁵Ca²⁺ uptake into log-phase cultures of S. cerevisiae strains that include combinations of Kch1, Kch2, Cch1, and the secreted protease Bar1 (strains K432, NZY164, NZY138, NZY165, EMY113) was measured after 4 h of incubation in SC-100 medium in the presence or absence of 10 μM α-factor (A) plus 0.2 μg of FK506/ml (B), as indicated. Averages for three biological replicates (± the standard deviations [SD]) are shown. (C) The wild-type strain and kch1, kch2, and kch1 kch2 double mutants with or without the functional CCH1 gene (strains CS12, CS01, CS02, CS03, CS04, CS05, CS06, CS07) all expressing cytoplasmic aequorin from a plasmid (pEVP11/AEQ89) were monitored for luminescence in YPD medium before and after the sudden jump to pH 9.