APC C components and main targets can be used to infer the phylogeny of eukaryotes Proteins inferred to have been present in LECA are valuable material to reconstruct the characteristics of this ancestral organism. In addition, they can preserve a phylogenetic signal useful to infer Axitinib VEGFR1 the evolutionary history of eukaryotes. Until now, most analyses dedicated to the reconstruction of the eukaryo tic phylogeny were based on the analysis of components of informational systems. This was so because most of the genes coding for these pro teins present the advantage of being part of mono genic gene families allowing the easy identification of orthologous proteins, slowly evolving, ancient and well conserved among life domains, and rarely exchanged by horizontal gene transfers.

Accordingly, they represent first choice material to investigate ancient evolution in all domains of life. Phylogenetic studies of the eukaryotic domain did not escape this rule and most of them have been largely based on the phylogenetic analysis of informational proteins. By contrast, most proteins involved in housekeeping functions are con sidered to evolve faster than those of informational sys tems, and thus to be less suitable to study ancient evolution. Moreover, they are often part of large and complex protein families that have experienced numer ous gene duplication and loss events during their evolu tionary history, meaning Brefeldin_A that distinguishing between orthologues and paralogues is difficult and requires fas tidious preliminary analyses.

Consequently, although these proteins are more numerous than informational ones and often of larger size, they have rarely been used to infer the ancient evolution of eukaryotes. Neverthe less, typical datasets based on informational proteins have been shown to be insufficient to robustly infer all the deep nodes of the global eukaryotic phylogenies. Increasing the protein sampling is therefore becoming as necessary as increasing the taxonomic sam pling find more information in order to fully resolve the phylogeny of eukar yotes, meaning that new useful protein markers have to be found among the conserved operational proteins. Our phylogenetic analyses of the APC C subunits and main targets showed that with a few exceptions they are ancient proteins well conserved throughout the diversity of present day eukaryotic lineages. Accordingly, they are potential suitable markers to reconstruct global eukaryo tic phylogenies. The maximum likelihood and Bayesian phylogenetic analyses of individual components showed that they have retained ancient phylogenetic signal despite the fact that some basal nodes of the inferred phylogenies showed a poor resolution.