FIG 4.

Ribosome binding of phosphosite mutant Asc1p variants. Asc1p phosphosite mutant strains were transformed with a plasmid bearing GFP-fused RPS2 (pHK697). Rps2p-GFP was pulled from cell extracts by use of GFP trap beads. Protein samples taken before the addition of the beads (input) and the proteins eluted from the GFP trap beads (eluate) were subjected to Western blot experiments. Immunodetection of Asc1p and Rps2p-GFP was performed using Asc1p- and GFP-specific antibodies, respectively. A wild-type strain expressing no GFP-tagged Asc1p was analyzed in parallel to exclude unspecific binding of Asc1p to the beads. Asterisks indicate protein bands that are supposed to be caused by processed Rps2p-GFP or Rps3p.