FIG. 7.

The noncatalytic transcriptional function of Mpk1 and Mlp1 is conserved in human ERK5. FKS2-lacZ reporter plasmids (wild-type, p2052; SBF-binding site mutant, p2053) were cotransformed with ERK5 expression plasmids into an mpk1Δ mlp1Δ strain (DL3196). ERK5 plasmids were wild-type (ERK5; p2349), ERK5-T219A Y221F (TAYF; p2350), ERK5-K84R (p2351), or vector (pUT34; p2348). Transformants were cultured as described in the legend of Fig. 1 in the presence of YEPD medium containing 10% sorbitol for osmotic support. β-Galactosidase (β-Gal) activity was measured in crude extracts. Each value represents the mean and standard deviation from three independent transformants. Sp. Act., specific activity; U, unit.