FIG 5.

RAC/Ssb and the ribosome-bound E3-ligase Ltn1 affect expression of Luc-K12t and Luc-RZt by distinct mechanisms. (A) The Δzuo1 and Δltn1 mutations synergistically enhance expression of Luc-K12t. Total extracts of the indicated strains expressing Luc-K12-3HA were analyzed via immunoblotting using antibodies recognizing luciferase (Luc) and, as a loading control, Sse1. The positions of Luc-K12-3HA (K12-3HA) and Luc-K12t (K12t) are indicated. (B) The effects of the Δzuo1 and Δltn1 mutations on Luc-K12t expression are additive. For each strain, the total intensity of the luciferase bands (Luc-K12-3HA plus Luc-K12t) was set at 100%. The intensity of the Luc-K12t band is given as a percentage of the total (see Materials and Methods). The results of 3 independent experiments are shown; error bars represent the standard errors of the means. wt, wild type. (C) The Δltn1, but not the Δzuo1, mutation enhances expression of Luc-RZt. Total extracts of the indicated strains expressing Luc-RZ-3HA were analyzed as described above for panel A. The positions of Luc-RZ-3HA (RZ-3HA) and Luc-RZt (RZt) are indicated. (D) The Δzuo1 mutation does not affect Luc-RZt expression in a Δltn1 strain. Analysis was performed as described above for panel B. The results of 3 independent experiments are shown; error bars represent the standard errors of the means.