title: Ancient origin of the integrin-mediated adhesion and signaling machinery.
abstract: The evolution of animals (metazoans) from their unicellular ancestors required the emergence of novel mechanisms for cell adhesion and cell-cell communication. One of the most important cell adhesion mechanisms for metazoan development is integrin-mediated adhesion and signaling. The integrin adhesion complex mediates critical interactions between cells and the extracellular matrix, modulating several aspects of cell physiology. To date this machinery has been considered strictly metazoan specific. Here we report the results of a comparative genomic analysis of the integrin adhesion machinery, using genomic data from several unicellular relatives of Metazoa and Fungi. Unexpectedly, we found that core components of the integrin adhesion complex are encoded in the genome of the apusozoan protist Amastigomonas sp., and therefore their origins predate the divergence of Opisthokonta, the clade that includes metazoans and fungi. Furthermore, our analyses suggest that key components of this apparatus have been lost independently in fungi and choanoflagellates. Our data highlight the fact that many of the key genes that had formerly been cited as crucial for metazoan origins have a much earlier origin. This underscores the importance of gene cooption in the unicellular-to-multicellular transition that led to the emergence of the Metazoa.
authors.affiliation: Departament de Genètica and Institut de Recerca en Biodiversitat, Universitat de Barcelona, 08028 Barcelona, Spain.
authors.forename: Arnau
authors.initials: A
authors.lastname: Sebé-Pedrós
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Roger
authors.forename: Franz B
authors.initials: FB
authors.lastname: Lang
authors.forename: Nicole
authors.initials: N
authors.lastname: King
authors.forename: Iñaki
authors.initials: I
authors.lastname: Ruiz-Trillo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000081247:CSK Tyrosine-Protein Kinase; D002448:Cell Adhesion / Q000235:genetics* / Q000502:physiology*; D002450:Cell Communication / Q000235:genetics / Q000502:physiology; D056897:Choanoflagellata / Q000235:genetics / Q000502:physiology; D000458:Cyanobacteria / Q000235:genetics / Q000502:physiology; D019143:Evolution, Molecular; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000235:genetics; D005658:Fungi / Q000235:genetics / Q000502:physiology; D022761:Gene Transfer, Horizontal; D016023:Integrins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D019061:src-Family Kinases
chemical_list: D016023:Integrins; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019061:src-Family Kinases