Figure 4.

Glucose-dependent degradation of Mth1 does not occur when Grr1 is removed from the nucleus. (A) GFP-Grr1 and GFP-Grr1ΔN (lacking the first 280 amino acids of Grr1) were expressed in the grr1Δ mutant (YM4783) in high-glucose medium (4%). (B) GFP-Mth1 was expressed alone (top) or coexpressed with Grr1-ΔN (bottom) in the grr1 mutant (YM4783). Subcellular localization of GFP-Mth1 and GFP-Grr1ΔN was analyzed by fluorescence microscopy (A and B). (C) GFP-Mth1 was expressed alone (top) or coexpressed with Grr1-ΔN (bottom) in the grr1 mutant (YM4783), and levels of GFP-Mth1 were analyzed by Western blotting using anti-GFP antibody. Yeast cells were grown in 2% galactose medium (Gal) or 4% glucose medium (Glu) as described in Figure 2.