Plots of proportion of EAR-containing proteins according to the protein localization in eukaryotic (A) and prokaryotic (B) organisms. Proteins are split into four groups: extracellular proteins with signal peptides (SP), transmembrane proteins (TM), nuclear proteins having nuclear localization signals (NLS) and other proteins that have been classified as cytosolic. The proportions of the analyzed proteins are as follows: in eukaryotes, 58.5% are cytosolic, 6.2% have SPs, 21.4% are transmembrane proteins and 13.9% have NLS. In prokaryotes, 71.9% are cytosolic, 4.3% have SPs and 23.7% are transmembrane proteins. For statistical analysis between the different cell compartments, we performed an ANOVA test for the predictors individually (ns: non-significant; ^*P <0.05; ^**P <0.01; ^***P <0.001; ^****P <0.0001).