Cell Cycle Regulation of pEg3, a New Xenopus Protein Kinase of the KIN1/PAR-1/MARK Family

Blot, Joëlle; Chartrain, Isabelle; Roghi, C; Tassan, Jean‐Pierre

doi:10.1006/dbio.2001.0525

Cited by 59 publications

(101 citation statements)

References 38 publications

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“…This residue was chosen after alignment with the Xenopus MELK protein kinase for which the corresponding K42R mutation led to a kinase dead enzyme. 44 The mutagenized Kin1-K154R Open Reading Frame was inserted into pREP41GFP in NdeI cloning sites and sequenced. Kin1Δ cells transformed with pREP41GFP-Kin1-K154R were not rescued (data not shown), indicating that the kinase activity of Kin1 is required to fulfil its cellular functions.…”

Section: Discussionmentioning

confidence: 99%

Role of the protein kinase Kin1 and nuclear centering in actomyosin ring formation in fission yeast

Cadou¹,

Carbona²,

Couturier³

et al. 2009

Cell Cycle

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Cytokinesis is the last step of the cell cycle, producing two daughter cells inheriting equal genetic information. This process involves the assembly of an actomyosin ring during mitosis. In the fission yeast Schizosaccharomyces pombe, cytokinesis occurs at the geometric cell centre, a position which is defined by the interphase nucleus and the anilin-related Mid1 protein. The pom1Δ, tea1Δ and tea4Δ mutants are defective in restricting Mid1 as a band around the nucleus and misplace the division site. We previously reported that inhibition of the protein kinase Kin1 promoted failure of cytokinesis in pom1Δ and tea1Δ cells but the mechanism involving Kin1 remained elusive. Here we investigated the contribution of Kin1 in cytokinesis. We show that Kin1-GFP has a dynamic cell cycle regulated distribution. Like pom1Δ and tea1Δ, tea4Δ exhibits a strong genetic interaction with kin1Δ. Using a conditional repressible kin1 allele that only alters interphase nuclear centering, we observed that Kin1 downregulation severely compromised actomyosin ring formation and septum synthesis in tea4Δ cells. In addition, nuclear displacement induced either by overexpression of a putative catalytically inactive Kin1 mutant, by chemically mediated microtubule depolymerization or by mutation in the par1Δ gene impaired cytokinesis in tea4Δ but not tea4 + cells. We propose that nuclear mispositioning exacerbates the tea4Δ, pom1Δ and tea1Δ cell division phenotype. Our work reveal that nuclear centering becomes essential when Pom1/Tea1/Tea4 function is compromised and that Kin1 expression level is a key regulatory element in this situation. Our results suggest the existence of distinct overlapping control mechanisms to ensure efficient cell division.

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Section: Discussionmentioning

confidence: 99%

Role of the protein kinase Kin1 and nuclear centering in actomyosin ring formation in fission yeast

Cadou¹,

Carbona²,

Couturier³

et al. 2009

Cell Cycle

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“…Reaction mixtures (20 µl) containing 600 ng CDC25B3 were incubated for 1 h at 30˚C with or without wild type or kinase-dead purified recombinant Eg3, 20 together with 50 µM ATP in kinase buffer except that the pH was raised to 8.2 to stabilize CDC25B. 29 A 10 µl aliquot of each reaction was then loaded onto a 10:0.13% acrylamide:bis-acrylamide gel for electrophoresis, and the remainder of each reaction was used to measure CDC25B phosphatase activity using FDP as the substrate.…”

Section: Antibodiesmentioning

confidence: 99%

“…17,18 We recently reported that CDC25B is phosphorylated on serine 323 by pEg3, a cell cycle-regulated protein kinase of the KIN1/PAR-1/MARK family. 19,20 This residue is equivalent to serine 216 of CDC25C, whose phosphorylation creates a 14.3.3 binding site that plays a critical role in the inactivation of CDC25C that occurs upon checkpoint activation after DNA damage. 21 We demonstrated that pEg3 is able to specifically associate with CDC25B in vitro and in vivo.…”

Section: Introductionmentioning

confidence: 99%

CDC25B Phosphorylated by pEg3 Localizes to the Centrosome and the Spindle Poles at Mitosis

Mirey

Chartrain²,

Froment³

et al. 2005

Cell Cycle

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The phosphatase CDC25B is one of the key regulators that control entry into mitosis through the dephosphorylation and subsequent activation of the cyclin-dependent kinases. Here we study the phosphorylation of CDC25B at mitosis by the kinase pEg3, a member of the KIN1/PAR-1/MARK family. Using mass spectrometry analysis we demonstrate that CDC25B is phosphorylated in vitro by pEg3 on serine 169, a residue that lies within the B domain. Moreover, using phosphoepitope-specific antibodies we show that serine 169 is phosphorylated in vivo, that this phosphorylated form of CDC25B accumulates during mitosis, and is localized to the centrosomes. This labelling is abrogated when pEg3 expression is repressed by RNA interference. Taken together, these results support a model in which pEg3 contributes to the control of progression through mitosis by phosphorylation of the CDC25 phosphatases.

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“…The KIN1/PAR-1/MARK protein family is composed of eukaryotic serine/threonine protein kinases that are predominantly conserved from yeasts to human in their N-terminal kinase catalytic domain and in the 40 C-terminal amino acids (Blot et al, 2002;Böhm et al, 1997;Drewes et al, 1998). In Caenorhabditis elegans, the par-1 gene was isolated in a genetic screen for par ("partitioning defective") mutations that led to the inability of one-cell stage embryo to partition asymmetrically cell fate determinants.…”

Section: Introductionmentioning

confidence: 99%

The protein kinase kin1 is required for cellular symmetry in fission yeast

Carbona

Allix

Maury

et al. 2004

Biology of the Cell

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The fission yeast Schizosaccharomyces pombe is a highly polarized unicellular eukaryote with two opposite growing poles in which F-actin cytoskeleton is focused. The KIN1/PAR-1/MARK protein family is composed of conserved eukaryotic serine/threonine kinases which are involved in cell polarity, microtubule stability or cell cycle regulation. Here, we investigate the function of the fission yeast KIN1/PAR-1/MARK member, kin1p. Using a deletion allele (kin1D), we show that kin1 mutation promotes a delay in septation. Kin1p regulates the structure of the new cell end after cytokinesis by modulating cell wall remodeling. Abnormal shaped interphase kin1D cells misplace F-actin patches and the premitotic nucleus. Thus, mitotic kin1D cells misposition the F-actin ring assembly site that is dependent on the position of the interphase nucleus. The resulting asymmetric cell division produces daughter cells with distinct shapes. Overexpressed kin1p accumulates asymmetrically at the cell cortex and affects cell shape, F-actin organization and microtubules. Our results suggest that correct dosage of kin1p at the cortex is required for spatial organization of the fission yeast cell.

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Cell Cycle Regulation of pEg3, a New Xenopus Protein Kinase of the KIN1/PAR-1/MARK Family

Cited by 59 publications

References 38 publications

Role of the protein kinase Kin1 and nuclear centering in actomyosin ring formation in fission yeast

Role of the protein kinase Kin1 and nuclear centering in actomyosin ring formation in fission yeast

CDC25B Phosphorylated by pEg3 Localizes to the Centrosome and the Spindle Poles at Mitosis

The protein kinase kin1 is required for cellular symmetry in fission yeast

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