FIG. 8.

CAK1 regulates the phosphorylation of Kin28p. (A) Genetic interaction between cak1-22 and kin28-ts16. The indicated wild-type (WT) and mutant strains (clockwise from top, YMW2, SY162, YJK1599, YJK1600, YGK24, and SY143) were plated and incubated at 26.5°C. Two isolates of wild-type and double-mutant strains are shown. (B) Kin28p is hypophosphorylated in a cak1-22 strain. Extracts were prepared from CAK1 and cak1-22 strains (YJK1610 and YJK1614, respectively) grown at 23 or 37°C for 6 h, and Kin28p immunoprecipitates were immunoblotted. (C) Extracts of a cak1-22 strain (YJK1625) grown at 37°C for 6 h were analyzed by 2-D gel electrophoresis as described for Fig. 2. Spots 3 and 4 correspond to the same Kin28p spots in Fig. 2.