Fig. 6. Deletion of imh1, but not ypt6, affects transport of Gas1p to the plasma membrane. (A) Congo Red hypersensitivity of ypt6- and imh1-mutant yeast cells. Serial dilutions of different mutants, as indicated, were spotted on plates of YPD, Congo Red (100 µg/ml), and Congo Red (100 µg/ml) containing 1.2 M sorbitol to examine their hypersensitivity. (B) Intracellular Gas1p ratio in arl1-, imh1- and ypt6-mutant yeast cells. Intracellular Gas1p ratio of wild-type, arl1, imh1 and ypt6 mutants were analyzed with a plasma membrane proteinase shaving assay as described in Materials and Methods. The ratio of intracellular Gas1p was calculated as described in Fig. 3B. (C) Statistical analysis of steady-state intracellular Gas1p in different mutant cells. The intracellular Gas1p ratio of three independent experiments was determined as described in Fig. 3B. ^*P<0.05; error bars represent the mean ± s.e.m.