Figure 7.

Degradation of a soluble form of Gas1^*p is independent of Bst1p function. (A) Construction of soluble forms of Gas1p (SHG) and Gas1^*p (SHg^*). SHG and SHg^* carry a stop codon instead of an asparagine (N528) just before the GPI anchoring signal of Gas1p. (B) SHG but not SHg^* is secreted into the medium. Cell lysates were prepared from exponentially growing cells. Proteins secreted into the medium were precipitated with 10% trichloroacetic acid. Samples corresponding to 0.5 OD₆₀₀ units of cells per lane were analyzed by immunoblotting. C, cell lysate; M, medium. (C) The degradation of SHg^* was measured in MFY325 (WT) and MFY326 (bst1Δ) cells, in which SHg^* is integrated at the URA3 locus as described in Figure 6. The results were quantified with an image analyzer, and the mean values ± SDs of three independent experiments are plotted, with the quantity at the 0 time point (steady-state level) set at 100%.