Evidence for the robustness of protein complexes to inter-species hybridization

PLoS Genet. 2012;8(12):e1003161. doi: 10.1371/journal.pgen.1003161. Epub 2012 Dec 27.


Despite the tremendous efforts devoted to the identification of genetic incompatibilities underlying hybrid sterility and inviability, little is known about the effect of inter-species hybridization at the protein interactome level. Here, we develop a screening platform for the comparison of protein-protein interactions (PPIs) among closely related species and their hybrids. We examine in vivo the architecture of protein complexes in two yeast species (Saccharomyces cerevisiae and Saccharomyces kudriavzevii) that diverged 5-20 million years ago and in their F1 hybrids. We focus on 24 proteins of two large complexes: the RNA polymerase II and the nuclear pore complex (NPC), which show contrasting patterns of molecular evolution. We found that, with the exception of one PPI in the NPC sub-complex, PPIs were highly conserved between species, regardless of protein divergence. Unexpectedly, we found that the architecture of the complexes in F1 hybrids could not be distinguished from that of the parental species. Our results suggest that the conservation of PPIs in hybrids likely results from the slow evolution taking place on the very few protein residues involved in the interaction or that protein complexes are inherently robust and may accommodate protein divergence up to the level that is observed among closely related species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Conserved Sequence
  • Evolution, Molecular
  • Hybridization, Genetic*
  • Multiprotein Complexes / genetics
  • Nuclear Pore / genetics*
  • Protein Interaction Maps
  • RNA Polymerase II / genetics*
  • Saccharomyces cerevisiae / genetics*
  • Species Specificity


  • Multiprotein Complexes
  • RNA Polymerase II

Grant support

This work was supported by a Natural Sciences and Engineering Research Council of Canada (NSERC) discovery grant to CRL and partly by a Genome Quebec grant, Human Frontier Science Program (HFSP) grant RGY0073/2010, and Canadian Institute of Health Research (CIHR) grant GMX-191597. J-BL was supported by a fellowship from the Fonds de Recherche en Santé du Québec (FRSQ). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.