Roles of Wis1, Win1, and Wis4 in the transmission of the arsenite signal. Spc1 phosphorylation (Spc1-P) was monitored in the wild type and in wis1Δ, wis1(AA), wis4Δ, win1-1, and wis4Δ win1-1 mutants. Cells were treated with 0.5 mM sodium arsenite. Spc1::HA was used as a loading control.