Effect of Nrg1 on SUC2 expression. (A) Expression levels of Nrg1-3HA in several yeast strains were determined by Western blotting with anti-HA antibodies. Lane 1, JD52 (wild type [WT], no tag), lane 2, RKY2176 (SNF7); lane 3, RKY2180 (Δsnf7); lane 4, RKY2284 (Δrim13); lane 5, RKY2285 (Δrim20); lane 6, RKY2286 (Δrim101). The arrow points to the main Nrg1-3HA band; the phosphorylated form is marked with an asterisk. (B) Yeast cells pregrown in YPD medium with 5% glucose were shifted to low-glucose medium (0.1%). At time intervals after the shift to low glucose, invertase activity was determined. Strains: closed squares, JD52 (WT); open squares, RKY1852 (Δsnf7); closed diamonds, RKY2175 (Δrim101); closed triangles, RKY2206 (Δnrg1); crosses, RKY2207 (Δnrg1 Δsnf7); and closed circles, RKY2208 (ADH1p-NRG1).