title: Cloning and characterisation of PKB and PRK homologs from Hydra and the evolution of the protein kinase family.
abstract: Two new serine/threonine protein kinases have been cloned from Hydra cDNA. The first of these kinases belongs to the PKB/Akt family. It is expressed ubiquitously in Hydra at a relatively low level but is upregulated during head regeneration. The second kinase is a member of the PRK/PKN family. It is ubiquitously expressed in Hydra tissue, albeit at a higher level than PKB. Construction of a phylogenetic tree including the Hydra PRK and PKB kinases and two PKC homologs previously cloned by Hassel and comparing them with members of the PKC, PKB and PRK families from porifera, Dictyostelium,yeast, Drosophila, Caenorhabditis and humans provide support for a simple model for the evolution of these kinase families. An ancestral precursor which contained a pleckstrin homology domain in its N-terminus and a C-terminal kinase domain gave rise to PKB in Dictyostelium. From this ancestor the PKB/PRK and PKC families evolved. The pleckstrin homology domain was lost in the PKC and PRK families and kept in the PKB family. PKB homologs have now been found in a variety of multicellular animals with Hydra being the phylogenetically earliest representative. Members of the PRK/PKC family, on the other hand, are also present in fungi. The precursor for these kinases must have contained N-terminal regulatory domains that were retained in fungal PRKs but subsequently partitioned between kinases of the PKC and PRK groups in metazoans.
authors.affiliation: Ludwig Maximilians-University Munich, Zoological Institute, Luisenstrasse 14, 80333 Munich, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Herold
authors.forename: Mihai
authors.initials: M
authors.lastname: Cikala
authors.forename: Harry
authors.initials: H
authors.lastname: MacWilliams
authors.forename: Charles N
authors.initials: CN
authors.lastname: David
authors.forename: Angelika
authors.initials: A
authors.lastname: Böttger
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D019143:Evolution, Molecular; D006829:Hydra / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010802:Phylogeny; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt