FIG. 2.

Growth defects associated with overexpression of a constitutively active MEK allele are altered by PTP expression level. (A) Overexpression of PTP2 suppressed the growth defect due to expression of the constitutively active MKK1 allele, MKK1-386, while strains lacking PTPs exacerbated these growth defects. Wild-type, ptp2Δ, ptp3Δ, and ptp2Δ ptp3Δ strains carrying pNV7MKK1386 and either YEplac112, p112PTP2, or p112PTP3 were grown in selective medium containing glucose. The cultures were normalized to 3.5 U (A₆₀₀); fivefold serial dilutions were made, spotted onto synthetic medium containing galactose (left panel) or glucose (right panel), and incubated at 30°C. (B) The catalytic activity of Ptp2 is important for suppression of the growth defect due to MKK1-386. Wild-type JD52 carrying pNV7MKK1386 and either p22PTP2C666A, p112PTP2C666A, or p22PTP2 was grown in synthetic medium containing glucose, and growth was examined as for panel A.