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A feedback loop in the polo-like kinase activation pathway.

Publication ,  Journal Article
Erikson, E; Haystead, TAJ; Qian, Y-W; Maller, JL
Published in: J Biol Chem
July 30, 2004

The Xenopus polo-like kinase Plx1 plays important roles during entry into and exit from mitosis (M phase). Previous studies revealed that Plx1 is activated by phosphorylation on serine and threonine residues, and purification of an activating enzyme from mitotic Xenopus egg extracts led to cloning and characterization of Xenopus polo-like kinase kinase (xPlkk1), which can phosphorylate and activate Plx1 in vitro. In the present study, a positive feedback loop between Plx1 and xPlkk1 was shown to result in each kinase phosphorylating and activating the other. Sequencing of radiolabeled xPlkk1 after phosphorylation by Plx1 in vitro identified three phosphorylation sites each spaced three amino acids apart, two of which have the consensus acidic-X-pSer-hydrophobic described for other polo-like kinase substrates. In addition, endogenous xPlkk1 in oocytes was phosphorylated on these sites in M phase but not in interphase. A mutant xPlkk1 in which these three amino acids were changed to alanine (xPlkk1(SA3)) was unable to be phosphorylated or activated in vitro by Plxl. Depletion of Plx1 from oocyte extracts prior to stimulation of the G(2)/M transition blocked the activation of xPlkk1, but depletion of xPlkk1 before stimulation did not block Plx1 activation. These results indicate that xPlkk1 may function downstream as a target of Plx1 rather than as an upstream activating kinase during the G(2)/M transition.

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Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

July 30, 2004

Volume

279

Issue

31

Start / End Page

32219 / 32224

Location

United States

Related Subject Headings

  • Xenopus laevis
  • Time Factors
  • Recombinant Proteins
  • Proto-Oncogene Proteins
  • Protein Serine-Threonine Kinases
  • Protein Kinases
  • Polo-Like Kinase 1
  • Phosphorylation
  • Oocytes
  • Mutation
 

Citation

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Erikson, E., Haystead, T. A. J., Qian, Y.-W., & Maller, J. L. (2004). A feedback loop in the polo-like kinase activation pathway. J Biol Chem, 279(31), 32219–32224. https://doi.org/10.1074/jbc.M403840200
Erikson, Eleanor, Timothy A. J. Haystead, Yue-Wei Qian, and James L. Maller. “A feedback loop in the polo-like kinase activation pathway.J Biol Chem 279, no. 31 (July 30, 2004): 32219–24. https://doi.org/10.1074/jbc.M403840200.
Erikson E, Haystead TAJ, Qian Y-W, Maller JL. A feedback loop in the polo-like kinase activation pathway. J Biol Chem. 2004 Jul 30;279(31):32219–24.
Erikson, Eleanor, et al. “A feedback loop in the polo-like kinase activation pathway.J Biol Chem, vol. 279, no. 31, July 2004, pp. 32219–24. Pubmed, doi:10.1074/jbc.M403840200.
Erikson E, Haystead TAJ, Qian Y-W, Maller JL. A feedback loop in the polo-like kinase activation pathway. J Biol Chem. 2004 Jul 30;279(31):32219–32224.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

July 30, 2004

Volume

279

Issue

31

Start / End Page

32219 / 32224

Location

United States

Related Subject Headings

  • Xenopus laevis
  • Time Factors
  • Recombinant Proteins
  • Proto-Oncogene Proteins
  • Protein Serine-Threonine Kinases
  • Protein Kinases
  • Polo-Like Kinase 1
  • Phosphorylation
  • Oocytes
  • Mutation