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Phosphorylation of mitotic kinesin-like protein 2 by polo-like kinase 1 is required for cytokinesis.

Neef R, Preisinger C, Sutcliffe J, Kopajtich R, Nigg EA, Mayer TU, Barr FA - J. Cell Biol. (2003)

Bottom Line: We have investigated the function of mitotic kinesin-like protein (MKlp) 2, a kinesin localized to the central spindle, and demonstrate that its depletion results in a failure of cleavage furrow ingression and cytokinesis, and disrupts localization of polo-like kinase 1 (Plk1).An antibody to the neck region of MKlp2 that prevents phosphorylation of MKlp2 by Plk1 causes a cytokinesis defect when introduced into cells.We propose that phosphorylation of MKlp2 by Plk1 is necessary for the spatial restriction of Plk1 to the central spindle during anaphase and telophase, and the complex of these two proteins is required for cytokinesis.

View Article: PubMed Central - PubMed

Affiliation: Intracellular Protein Transport, Independent Junior Research Group, Max-Planck-Institute of Biochemistry, 82152 Martinsried, Germany.

ABSTRACT
We have investigated the function of mitotic kinesin-like protein (MKlp) 2, a kinesin localized to the central spindle, and demonstrate that its depletion results in a failure of cleavage furrow ingression and cytokinesis, and disrupts localization of polo-like kinase 1 (Plk1). MKlp2 is a target for Plk1, and phosphorylated MKlp2 binds to the polo box domain of Plk1. Plk1 also binds directly to microtubules and targets to the central spindle via its polo box domain, and this interaction controls the activity of Plk1 toward MKlp2. An antibody to the neck region of MKlp2 that prevents phosphorylation of MKlp2 by Plk1 causes a cytokinesis defect when introduced into cells. We propose that phosphorylation of MKlp2 by Plk1 is necessary for the spatial restriction of Plk1 to the central spindle during anaphase and telophase, and the complex of these two proteins is required for cytokinesis.

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Plk1 and MKlp2 form a microtubule-sensing device at the central spindle. Early in anaphase as the chromosomes (blue) are partitioned, MKlp2 is recruited to the forming microtubule bundles that will give rise to the central spindle. Plk1, although able to weakly associate with microtubules (green), is not present on all microtubule structures, and therefore must have additional specificity factors in order to localize properly; MKlp2 appears to be one such factor. Plk1 associates with microtubules and phosphorylates MKlp2, to which it can then bind and thus maintain a stable association with the central spindle. We propose that this MKlp2-associated and thus spatially restricted pool of Plk1 can then phosphorylate other targets at the central spindle and cleavage furrow to control cleavage furrow ingression and cytokinesis. Red arrows indicate phosphorylation events.
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fig9: Plk1 and MKlp2 form a microtubule-sensing device at the central spindle. Early in anaphase as the chromosomes (blue) are partitioned, MKlp2 is recruited to the forming microtubule bundles that will give rise to the central spindle. Plk1, although able to weakly associate with microtubules (green), is not present on all microtubule structures, and therefore must have additional specificity factors in order to localize properly; MKlp2 appears to be one such factor. Plk1 associates with microtubules and phosphorylates MKlp2, to which it can then bind and thus maintain a stable association with the central spindle. We propose that this MKlp2-associated and thus spatially restricted pool of Plk1 can then phosphorylate other targets at the central spindle and cleavage furrow to control cleavage furrow ingression and cytokinesis. Red arrows indicate phosphorylation events.

Mentions: Spatial control of mitotic kinases is becoming an increasingly important area for the understanding of how cells regulate many events during cell division (Pines, 1999). Our data suggest a mechanism for the spatial restriction of Plk1 signaling to the central spindle during anaphase and telophase (Fig. 9). This is not the only example where spatially restricted Plk1 signaling may play a key role in regulation of cell division. Plk1 is important for the localized activation of the cdk1–cyclin B1 complex at the centrosomes and for the triggering of mitosis (Jackman et al., 2003). Although it is unknown how Plk1 is regulated in this case, its association with the key cellular microtubule-nucleating structure, the centrosome, indicates that microtubules are also likely to be important for controlling Plk1 activity in this context. Similarly, the identity of the microtubule-sensing component at the kinetochores monitoring chromosome capture is still unknown, and our results suggest that Plk1 could be a component of such a microtubule sensor. These proposals highlight the general importance of the finding that Plk1 binds to and is regulated by microtubules. The identification and characterization of further Plk1 substrates and interacting partners at the central spindle, kinetochores, and centrosomes will help address the generality of this proposal.


Phosphorylation of mitotic kinesin-like protein 2 by polo-like kinase 1 is required for cytokinesis.

Neef R, Preisinger C, Sutcliffe J, Kopajtich R, Nigg EA, Mayer TU, Barr FA - J. Cell Biol. (2003)

Plk1 and MKlp2 form a microtubule-sensing device at the central spindle. Early in anaphase as the chromosomes (blue) are partitioned, MKlp2 is recruited to the forming microtubule bundles that will give rise to the central spindle. Plk1, although able to weakly associate with microtubules (green), is not present on all microtubule structures, and therefore must have additional specificity factors in order to localize properly; MKlp2 appears to be one such factor. Plk1 associates with microtubules and phosphorylates MKlp2, to which it can then bind and thus maintain a stable association with the central spindle. We propose that this MKlp2-associated and thus spatially restricted pool of Plk1 can then phosphorylate other targets at the central spindle and cleavage furrow to control cleavage furrow ingression and cytokinesis. Red arrows indicate phosphorylation events.
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Related In: Results  -  Collection

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fig9: Plk1 and MKlp2 form a microtubule-sensing device at the central spindle. Early in anaphase as the chromosomes (blue) are partitioned, MKlp2 is recruited to the forming microtubule bundles that will give rise to the central spindle. Plk1, although able to weakly associate with microtubules (green), is not present on all microtubule structures, and therefore must have additional specificity factors in order to localize properly; MKlp2 appears to be one such factor. Plk1 associates with microtubules and phosphorylates MKlp2, to which it can then bind and thus maintain a stable association with the central spindle. We propose that this MKlp2-associated and thus spatially restricted pool of Plk1 can then phosphorylate other targets at the central spindle and cleavage furrow to control cleavage furrow ingression and cytokinesis. Red arrows indicate phosphorylation events.
Mentions: Spatial control of mitotic kinases is becoming an increasingly important area for the understanding of how cells regulate many events during cell division (Pines, 1999). Our data suggest a mechanism for the spatial restriction of Plk1 signaling to the central spindle during anaphase and telophase (Fig. 9). This is not the only example where spatially restricted Plk1 signaling may play a key role in regulation of cell division. Plk1 is important for the localized activation of the cdk1–cyclin B1 complex at the centrosomes and for the triggering of mitosis (Jackman et al., 2003). Although it is unknown how Plk1 is regulated in this case, its association with the key cellular microtubule-nucleating structure, the centrosome, indicates that microtubules are also likely to be important for controlling Plk1 activity in this context. Similarly, the identity of the microtubule-sensing component at the kinetochores monitoring chromosome capture is still unknown, and our results suggest that Plk1 could be a component of such a microtubule sensor. These proposals highlight the general importance of the finding that Plk1 binds to and is regulated by microtubules. The identification and characterization of further Plk1 substrates and interacting partners at the central spindle, kinetochores, and centrosomes will help address the generality of this proposal.

Bottom Line: We have investigated the function of mitotic kinesin-like protein (MKlp) 2, a kinesin localized to the central spindle, and demonstrate that its depletion results in a failure of cleavage furrow ingression and cytokinesis, and disrupts localization of polo-like kinase 1 (Plk1).An antibody to the neck region of MKlp2 that prevents phosphorylation of MKlp2 by Plk1 causes a cytokinesis defect when introduced into cells.We propose that phosphorylation of MKlp2 by Plk1 is necessary for the spatial restriction of Plk1 to the central spindle during anaphase and telophase, and the complex of these two proteins is required for cytokinesis.

View Article: PubMed Central - PubMed

Affiliation: Intracellular Protein Transport, Independent Junior Research Group, Max-Planck-Institute of Biochemistry, 82152 Martinsried, Germany.

ABSTRACT
We have investigated the function of mitotic kinesin-like protein (MKlp) 2, a kinesin localized to the central spindle, and demonstrate that its depletion results in a failure of cleavage furrow ingression and cytokinesis, and disrupts localization of polo-like kinase 1 (Plk1). MKlp2 is a target for Plk1, and phosphorylated MKlp2 binds to the polo box domain of Plk1. Plk1 also binds directly to microtubules and targets to the central spindle via its polo box domain, and this interaction controls the activity of Plk1 toward MKlp2. An antibody to the neck region of MKlp2 that prevents phosphorylation of MKlp2 by Plk1 causes a cytokinesis defect when introduced into cells. We propose that phosphorylation of MKlp2 by Plk1 is necessary for the spatial restriction of Plk1 to the central spindle during anaphase and telophase, and the complex of these two proteins is required for cytokinesis.

Show MeSH