A1 Journal article – refereed
Early Chordate Origin of the Vertebrate Integrin αI Domains

List of Authors: Bhanupratap Singh Chouhan,Jarmo Käpylä,Konstantin Denessiouk, Alexander Denesyuk,Jyrki Heino,Mark S. Johnson
Publication year: 2014
Journal: PLoS ONE
Journal name in source: PloS one
Journal acronym: PLoS One
Volume number: 9
Issue number: 11
ISSN: 1932-6203


Half of the 18 human integrins α subunits have an inserted αI domain yet none have been observed in species that have diverged prior to the appearance of the urochordates (ascidians). The urochordate integrin αI domains are not human orthologues but paralogues, but orthologues of human αI domains extend throughout later-diverging vertebrates and are observed in the bony fish with duplicate isoforms. Here, we report evidence for orthologues of human integrins with αI domains in the agnathostomes (jawless vertebrates) and later diverging species. Sequence comparisons, phylogenetic analyses and molecular modeling show that one nearly full-length sequence from lamprey and two additional fragments include the entire integrin αI domain region, have the hallmarks of collagen-binding integrin αI domains, and we show that the corresponding recombinant proteins recognize the collagen GFOGER motifs in a metal dependent manner, unlike the α1I domain of the ascidian C. intestinalis. The presence of a functional collagen receptor integrin αI domain supports the origin of orthologues of the human integrins with αI domains prior to the earliest diverging extant vertebrates, a domain that has been conserved and diversified throughout the vertebrate lineage.

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Last updated on 2019-21-08 at 22:40