FIG. 2.

The constitutive SSY5 and PTR3 mutants exhibit increased levels of Stp1p processing in the absence of amino acids. Strains M5444 (ssy5Δ STP1-ZZ, first three lanes) and M5443 (ptr3Δ STP1-ZZ, last four lanes) transformed with centromere-based plasmid pRS316 carrying the indicated PTR3 and SSY5 alleles were grown in minimal medium (SD medium), and total protein was extracted and subjected to Western analysis of Stp1p-ZZ processing. The percentages of processed Stp1-ZZ in proportion to total Stp1-ZZ are indicated. The standard errors of the means of at least two experiments are shown in parentheses. U, unprocessed Stp1p-ZZ; P, processed Stp1p-ZZ.