Cell cycle regulation of pEg3, a new Xenopus protein kinase of the KIN1/PAR-1/MARK family.
We report the characterization of pEg3, a Xenopus protein kinase related to members of the KIN1/PAR-1/MARK family. The founding members of this newly emerging kinase family were shown to be involved in the establishment of cell polarity and both microtubule dynamic and cytoskeleton organization. Sequence analyses suggest that pEg3 and related protein kinases in human, mouse, and Caenorhabditis elegans might constitute a distinct group in this family. pEg3 is encoded by a maternal mRNA, polyadenylated in unfertilized eggs and specifically deadenylated in embryos. In addition to an increase in expression, we have shown that pEg3 is phosphorylated during oocyte maturation. Phosphorylation of pEg3 is cell cycle dependent during Xenopus early embryogenesis and in synchronized cultured XL2 cells. In embryos, the kinase activity of pEg3 is correlated to its phosphorylation state and is maximum during mitosis. Using Xenopus egg extracts we demonstrated that phosphorylation occurs at least in the noncatalytic domain of the kinase, suggesting that this domain might be important for pEg3 function.
Blot
Joëlle
J
UMR 6061, Centre National de la Recherche Scientifique, IFR 97, Université de Rennes 1, 2 avenue du Professeur Léon Bernard, CS34317, F-35043 Rennes Cedex, France.
Chartrain
Isabelle
I
Roghi
Christian
C
Philippe
Michel
M
Tassan
Jean-Pierre
JP
D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000235:genetics; D004527:Egg Proteins / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000201:enzymology / Q000648:ultrastructure; D004790:Enzyme Induction; D008938:Mitosis; D008969:Molecular Sequence Data; D005810:Multigene Family; D009865:Oocytes / Q000201:enzymology; D010750:Phosphoproteins / Q000235:genetics / Q000502:physiology; D010766:Phosphorylation; D011494:Protein Kinases / Q000145:classification / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D029867:Xenopus Proteins / Q000235:genetics / Q000502:physiology*; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics* / Q000378:metabolism
D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D004527:Egg Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D029867:Xenopus Proteins; D011494:Protein Kinases; C447600:pEg3 protein, Xenopus