Membrane trafficking is central for eukaryotic evolution. (A) Distribution of proteins from H. sapiens, S. cerevisiae, A. thaliana and E. histolytica after reciprocal best hit analysis. Proteins of a given organism are assigned to one of the 15 categories according to the number of orthologues and the species in which they are found. (B) Analysis of the 245 proteins common to Opisthokonta and absent/divergent in Plantae and Protist by the S. cerevisiae GO (Gene Ontology) database. Only categories with a P-value inferior to 10-4 and comprising more than 3 proteins were retained. Categories highlighted in red are involved in cytokinesis, in yellow in membrane trafficking and in green in metabolic processes. (C) Analysis of the 280 proteins common to S. cerevisiae and A. thaliana by the S. cerevisiae GO database. The same category color code as used in (B) was applied. (D) The total number of proteins involved in each process (unknown function, other functions, trafficking, cytokinesis or metabolism) based on the S. cerevisiae GO database was represented and this irrespective of their involvement in more than one process. (E) Relative distribution of bifunctional proteins involved in trafficking-cytokinesis, trafficking-metabolism and cytokinesis-metabolism.