FIGURE 4.

Tco89p is required for the degradation of FBPase, MDH2, Icl1p, and Pck1p. A, wild type (WT) cells and cells lacking TCO89 were starved for 3 days. Cells were then transferred to media containing fresh glucose for 0 and 3 h. The degradation of FBPase, MDH2, Icl1p, and Pck1p was examined. B, left panel, wild type strain expressing Tco89p-myc was starved for 3 days. FBPase was immunoprecipitated from total lysates at t = 0 min. The bound and unbound fractions were subjected to immunoblotting with anti-FBPase and anti-myc antibodies. Right panel, Tco89p-protein A fusion proteins were precipitated from wild type cells that were refed with fresh glucose for the indicated times. The bound fractions were blotted with anti-FBPase antibodies. C, Tco89p-V5-His₆ fusion proteins were precipitated from wild type cells that expressed Pck1p-HA or Icl1p-HA. The presence of MDH2, Pck1p and Icl1p in the unbound (U) and bound (B) fractions was detected by Western blotting.