FIG. 4.

Effect of gpb1Δ gpb2Δ mutations is independent of the low-affinity cAMP phosphodiesterase. (A) Extracts made from the following strains expressing Msn2p-GFP fusion protein from plasmid pAdh1-Msn2-GFP were analyzed by SDS-PAGE and immunoblotting with antibodies to P-CREB (S133) and GFP: wild-type strain SKY762 (lane 1), gpb1Δ gpb2Δ strain HS182-3B (lane 2), pde1Δ strain SKY.p1k (lane 3), gpb1Δ gpb2Δ pde1Δ strain HS182-3B.p1k (lane 4). (B) The strains described in panel A were grown to saturation for 2 days in synthetic complete medium, incubated at 50°C for 15 min, and diluted and plated to determine the percent survival. Values for GPB1 GPB2 strains are represented by the open bars; values for gpb1Δ gpb2Δ strains are represented by the filled bars. Values shown are the mean and standard deviation from three independent experiments.