FIG. 3.

Mutations in the substrate-binding site and the D-motif-binding site of Mpk1 cause differential phenotypes. An mpk1Δ strain (yeast strain DL456) was transformed with centromeric plasmids expressing the indicated alleles of MPK1 or empty vector (pRS315). Transformants were grown overnight to saturation in selective medium (SD lacking Leu), and serial 10-fold dilutions were plated by pin plating from 96-well plates onto YPD alone or YPD plus 8 mM caffeine and incubated at the indicated temperature for 2 days.