title: Eukaryotic signalling domain homologues in archaea and bacteria. Ancient ancestry and horizontal gene transfer.
abstract: Phyletic distributions of eukaryotic signalling domains were studied using recently developed sensitive methods for protein sequence analysis, with an emphasis on the detection and accurate enumeration of homologues in bacteria and archaea. A major difference was found between the distributions of enzyme families that are typically found in all three divisions of cellular life and non-enzymatic domain families that are usually eukaryote-specific. Previously undetected bacterial homologues were identified for# plant pathogenesis-related proteins, Pad1, von Willebrand factor type A, src homology 3 and YWTD repeat-containing domains. Comparisons of the domain distributions in eukaryotes and prokaryotes enabled distinctions to be made between the domains originating prior to the last common ancestor of all known life forms and those apparently originating as consequences of horizontal gene transfer events. A number of transfers of signalling domains from eukaryotes to bacteria were confidently identified, in contrast to only a single case of apparent transfer from eukaryotes to archaea.
authors.affiliation: National Center for Biotechnology Information National Library of Medicine, National Institutes of Health, Bldg. 38A, Bethesda, MD, 20894, USA. ponting@ncbi.nlm.nih.gov
authors.forename: C P
authors.initials: CP
authors.lastname: Ponting
authors.forename: L
authors.initials: L
authors.lastname: Aravind
authors.forename: J
authors.initials: J
authors.lastname: Schultz
authors.forename: P
authors.initials: P
authors.lastname: Bork
authors.forename: E V
authors.initials: EV
authors.lastname: Koonin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D017173:Caenorhabditis elegans / Q000235:genetics*; D004798:Enzymes / Q000235:genetics; D005057:Eukaryotic Cells; D019143:Evolution, Molecular; D019766:Genes, Archaeal; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010802:Phylogeny; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D018909:src Homology Domains
chemical_list: D004798:Enzymes