FIGURE 4.

β and γ subunits are required for ADP-mediated protection. A, phosphatase protection assays were performed in triplicate using full-length Snf1 protein purified from cells lacking the genes for the γ subunit and all three β subunits (snf4Δ sip1Δ sip2Δ gal83Δ). The mean ratio of phosphorylated Snf1 (Snf1-P) to total Snf1 is plotted as the percentage remaining after phosphatase treatment. Representative blots are shown below. ns (not significant), p > 0.05. B, an SDS protein gel stained with silver nitrate was used to assess the purity and integrity of the Snf1 protein used in this experiment. The Snf1 complex purified from wild-type cells was loaded for comparison. The mobility of molecular mass markers (M) is indicated in kilodaltons on the left.