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Elm1 kinase activates the spindle position checkpoint kinase Kin4.

Caydasi AK, Kurtulmus B, Orrico MI, Hofmann A, Ibrahim B, Pereira G - J. Cell Biol. (2010)

Bottom Line: How Kin4 kinase activity is regulated and maintained in respect to spindle positional cues remains to be established.Here, we show that the bud neck-associated kinase Elm1 participates in Kin4 activation and SPOC signaling by phosphorylating a conserved residue within the activation loop of Kin4.Blocking Elm1 function abolishes Kin4 kinase activity in vivo and eliminates the SPOC response to spindle misalignment.

View Article: PubMed Central - HTML - PubMed

Affiliation: German Cancer Research Center, DKFZ-ZMBH Alliance, Molecular Biology of Centrosomes and Cilia, 69120 Heidelberg, Germany.

ABSTRACT
Budding yeast asymmetric cell division relies upon the precise coordination of spindle orientation and cell cycle progression. The spindle position checkpoint (SPOC) is a surveillance mechanism that prevents cells with misoriented spindles from exiting mitosis. The cortical kinase Kin4 acts near the top of this network. How Kin4 kinase activity is regulated and maintained in respect to spindle positional cues remains to be established. Here, we show that the bud neck-associated kinase Elm1 participates in Kin4 activation and SPOC signaling by phosphorylating a conserved residue within the activation loop of Kin4. Blocking Elm1 function abolishes Kin4 kinase activity in vivo and eliminates the SPOC response to spindle misalignment. These findings establish a novel function for Elm1 in the coordination of spindle positioning with cell cycle progression via its control of Kin4.

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Localization and SPOC activity of KIN4 mutants. (A) The indicated strains were incubated at 30°C for 3 h before fixation. The percentage of cells with normal (white bars), misaligned (gray bars), and broken spindles in one cell body (black bars, SPOC-deficient cells) are indicated. (B) Kin4-GFP localization was scored for the indicated strains. The graphs in A and B show one representative experiment out of three; 100–150 cells were counted per sample.
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fig7: Localization and SPOC activity of KIN4 mutants. (A) The indicated strains were incubated at 30°C for 3 h before fixation. The percentage of cells with normal (white bars), misaligned (gray bars), and broken spindles in one cell body (black bars, SPOC-deficient cells) are indicated. (B) Kin4-GFP localization was scored for the indicated strains. The graphs in A and B show one representative experiment out of three; 100–150 cells were counted per sample.

Mentions: To study the function of Elm1 phosphorylation of Kin4 at position T209, we analyzed the phenotypes of cells with the nonphosphorylatable Kin4-T209A. As shown previously, the T209A substitution completely abolished Kin4 kinase activity in vivo and in vitro (Fig. 4 C). Moreover, cells carrying kin4-T209A were SPOC deficient (Fig. 7 A; D’Aquino et al., 2005; Maekawa et al., 2007). We also established that protein levels and Kin4 localization were not affected by the T209A (Figs. 7 B and S3 F). Together, these data strongly support the view that phosphorylation of T209 by Elm1 promotes Kin4 catalytic activity and thereby SPOC proficiency.


Elm1 kinase activates the spindle position checkpoint kinase Kin4.

Caydasi AK, Kurtulmus B, Orrico MI, Hofmann A, Ibrahim B, Pereira G - J. Cell Biol. (2010)

Localization and SPOC activity of KIN4 mutants. (A) The indicated strains were incubated at 30°C for 3 h before fixation. The percentage of cells with normal (white bars), misaligned (gray bars), and broken spindles in one cell body (black bars, SPOC-deficient cells) are indicated. (B) Kin4-GFP localization was scored for the indicated strains. The graphs in A and B show one representative experiment out of three; 100–150 cells were counted per sample.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3101594&req=5

fig7: Localization and SPOC activity of KIN4 mutants. (A) The indicated strains were incubated at 30°C for 3 h before fixation. The percentage of cells with normal (white bars), misaligned (gray bars), and broken spindles in one cell body (black bars, SPOC-deficient cells) are indicated. (B) Kin4-GFP localization was scored for the indicated strains. The graphs in A and B show one representative experiment out of three; 100–150 cells were counted per sample.
Mentions: To study the function of Elm1 phosphorylation of Kin4 at position T209, we analyzed the phenotypes of cells with the nonphosphorylatable Kin4-T209A. As shown previously, the T209A substitution completely abolished Kin4 kinase activity in vivo and in vitro (Fig. 4 C). Moreover, cells carrying kin4-T209A were SPOC deficient (Fig. 7 A; D’Aquino et al., 2005; Maekawa et al., 2007). We also established that protein levels and Kin4 localization were not affected by the T209A (Figs. 7 B and S3 F). Together, these data strongly support the view that phosphorylation of T209 by Elm1 promotes Kin4 catalytic activity and thereby SPOC proficiency.

Bottom Line: How Kin4 kinase activity is regulated and maintained in respect to spindle positional cues remains to be established.Here, we show that the bud neck-associated kinase Elm1 participates in Kin4 activation and SPOC signaling by phosphorylating a conserved residue within the activation loop of Kin4.Blocking Elm1 function abolishes Kin4 kinase activity in vivo and eliminates the SPOC response to spindle misalignment.

View Article: PubMed Central - HTML - PubMed

Affiliation: German Cancer Research Center, DKFZ-ZMBH Alliance, Molecular Biology of Centrosomes and Cilia, 69120 Heidelberg, Germany.

ABSTRACT
Budding yeast asymmetric cell division relies upon the precise coordination of spindle orientation and cell cycle progression. The spindle position checkpoint (SPOC) is a surveillance mechanism that prevents cells with misoriented spindles from exiting mitosis. The cortical kinase Kin4 acts near the top of this network. How Kin4 kinase activity is regulated and maintained in respect to spindle positional cues remains to be established. Here, we show that the bud neck-associated kinase Elm1 participates in Kin4 activation and SPOC signaling by phosphorylating a conserved residue within the activation loop of Kin4. Blocking Elm1 function abolishes Kin4 kinase activity in vivo and eliminates the SPOC response to spindle misalignment. These findings establish a novel function for Elm1 in the coordination of spindle positioning with cell cycle progression via its control of Kin4.

Show MeSH
Related in: MedlinePlus