Proteomics analysis of the effect of deletion and mutation of eIF4E binding proteins Caf20 and Eap1 on yeast via LC-MSMS.

There are multiple translational control pathways. These include pathways involving eIF4E binding proteins (4E-BPs), which inhibit translation by binding and sequestering the 5’ cap binding protein eIF4E away from its partner eIF4G. Saccharomyces cerevisiae has two 4E-BPs: Caf20p and Eap1p; and, microarray analysis has shown that each regulates different subsets of mRNAs. To assess the effect of these different regulatory responses at the protein level, we used label-free mass spectrometry to compare the proteomes of wild-type strain with those of caf20Δ and eap1Δ single mutant strains; caf20Δ and eap1Δ double mutant strain; and, caf20Δ mutant strain transformed with one plasmid containing a mutated version of caf20. These analyses indicate that Caf20p and Eap1p may compensate for each other loss, and also reveal that Caf20p participates in translational control pathways that are independent of eIF4E binding.