title: Interkingdom complementation reveals structural conservation and functional divergence of 14-3-3 proteins.
abstract: The 14-3-3s are small acidic cytosolic proteins that interact with multiple clients and participate in essential cellular functions in all eukaryotes. Available structural and functional information about 14-3-3s is largely derived from higher eukaryotes, which contain multiple members of this protein family suggesting functional specialization. The exceptional sequence conservation among 14-3-3 family members from diverse species suggests a common ancestor for 14-3-3s, proposed to have been similar to modern 14-3-3ε isoforms. Structural features of the sole family member from the protozoan Giardia duodenalis (g14-3-3), are consistent with this hypothesis, but whether g14-3-3 is functionally homologous to the epsilon isoforms is unknown. We use inter-kingdom reciprocal functional complementation and biochemical methods to determine whether g14-3-3 is structurally and functionally homologous with members of the two 14-3-3 conservation groups of the metazoan Drosophila melanogaster. Our results indicate that although g14-3-3 is structurally homologous to D14-3-3ε, functionally it diverges presenting characteristics of other 14-3-3s. Given the basal position of Giardia in eukaryotic evolution, this finding is consistent with the hypothesis that 14-3-3ε isoforms are ancestral to other family members.
authors.affiliation: Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Lalle
authors.forename: Flora
authors.initials: F
authors.lastname: Leptourgidou
authors.forename: Serena
authors.initials: S
authors.lastname: Camerini
authors.forename: Edoardo
authors.initials: E
authors.lastname: Pozio
authors.forename: Efthimios M C
authors.initials: EM
authors.lastname: Skoulakis
mesh_terms: D048948:14-3-3 Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D004331:Drosophila melanogaster; D019143:Evolution, Molecular; D016829:Giardia lamblia / Q000378:metabolism; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
chemical_list: D048948:14-3-3 Proteins