Figure 3. Proteomic analysis of RP-deficient imaginal discs.

(a) Volcano plot displaying changes in the abundance of proteins in RPS23^R67K/+ relative to wild type. The green dot highlights IRBP18, while red dots show all the proteins annotated as being involved in ribosome biogenesis (as determined from flybase.org and/or Uniprot) that are changed in a statistically significant manner. The plot also displays the changes in the abundance of ribosomal proteins in RPS23^R67K/+ relative to wild type. On average, proteins of the small subunit (RPS, orange circles) are underrepresented while those of the large subunit (RPL, blue circles) are enriched in mutant discs. (b) Differential effect of RP deficiency on the abundance of small (orange) and large (blue) subunit proteins. Since only half the complement of functional RPS23 is produced in the RPS23^R67K heterozygotes, a large number of small subunit proteins are orphaned and must be disposed of. By contrast, all the large subunit proteins produced by the cell can assemble in complete subunits. Coloured proteins highlighted in a are listed in Supplementary Table 2.