The first green lineage cdc25 dual-specificity phosphatase.
The Cdc25 protein phosphatase is a key enzyme involved in the regulation of the G(2)/M transition in metazoans and yeast. However, no Cdc25 ortholog has so far been identified in plants, although functional studies have shown that an activating dephosphorylation of the CDK-cyclin complex regulates the G(2)/M transition. In this paper, the first green lineage Cdc25 ortholog is described in the unicellular alga Ostreococcus tauri. It encodes a protein which is able to rescue the yeast S. pombe cdc25-22 conditional mutant. Furthermore, microinjection of GST-tagged O. tauri Cdc25 specifically activates prophase-arrested starfish oocytes. In vitro histone H1 kinase assays and anti-phosphotyrosine Western Blotting confirmed the in vivo activating dephosphorylation of starfish CDK1-cyclinB by recombinant O. tauri Cdc25. We propose that there has been coevolution of the regulatory proteins involved in the control of M-phase entry in the metazoan, yeast and green lineages.
Université Paris VI, Laboratoire Arago, Modèles en Biologie Cellulaire et Evolutive, Banyuls sur Mer, France.
B
B
Khadaroo
S
S
Robbens
C
C
Ferraz
E
E
Derelle
S
S
Eychenié
R
R
Cooke
G
G
Peaucellier
M
M
Delseny
J
J
Demaille
Y
Y
Van de Peer
A
A
Picard
H
H
Moreau
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D019070:Cell Lineage; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D016195:G2 Phase; D005982:Glutathione Transferase / Q000378:metabolism; D008938:Mitosis; D008969:Molecular Sequence Data; D009154:Mutation; D009865:Oocytes / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D010802:Phylogeny; D011494:Protein Kinases / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D012568:Schizosaccharomyces / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013215:Starfish; D013696:Temperature; D013997:Time Factors; D020687:cdc25 Phosphatases / Q000737:chemistry* / Q000378:metabolism
D018797:Cell Cycle Proteins; D011994:Recombinant Proteins; D019000:Phosphotyrosine; D005982:Glutathione Transferase; D011494:Protein Kinases; C102333:histone H1 kinase; D010744:Phosphoric Monoester Hydrolases; D020687:cdc25 Phosphatases