title: Nonplastid eukaryotic response regulators have a monophyletic origin and evolved from their bacterial precursors in parallel with their cognate sensor kinases.
abstract: We have analyzed all currently sequenced eukaryotic proteins containing either a kinase module or a receiver module, corresponding to those found in bacterial sensor kinases or response regulators, respectively, of the so-called two-component regulatory systems. We demonstrate that the eukaryotic receiver modules belong to a single subfamily of the bacterial receiver modules. Moreover, the cognate eukaryotic kinase modules exhibit a similar clustering pattern on the sensor kinase phylogenetic tree, suggesting that they evolved in parallel with the receiver modules from a common ancestral source that bore both modules. Multiple alignments of the sequences corresponding to these modules are presented and discussed, and eukaryotic-specific signature sequences are derived.
authors.affiliation: Department of Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA.
authors.forename: G M
authors.initials: GM
authors.lastname: Pao
authors.forename: M H
authors.initials: MH
authors.lastname: Saier
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010770:Phosphotransferases / Q000235:genetics*; D010802:Phylogeny; D016415:Sequence Alignment; D017421:Sequence Analysis
chemical_list: D010770:Phosphotransferases