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Cell cycle regulation of the activity and subcellular localization of Plk1, a human protein kinase implicated in mitotic spindle function..pdf (2.19 MB)

Cell cycle regulation of the activity and subcellular localization of Plk1, a human protein kinase implicated in mitotic spindle function.

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journal contribution
posted on 2016-12-15, 11:05 authored by R. M. Golsteyn, K. E. Mundt, A. M. Fry, E. A. Nigg
Correct assembly and function of the mitotic spindle during cell division is essential for the accurate partitioning of the duplicated genome to daughter cells. Protein phosphorylation has long been implicated in controlling spindle function and chromosome segregation, and genetic studies have identified several protein kinases and phosphatases that are likely to regulate these processes. In particular, mutations in the serine/threonine-specific Drosophila kinase polo, and the structurally related kinase Cdc5p of Saccharomyces cerevisae, result in abnormal mitotic and meiotic divisions. Here, we describe a detailed analysis of the cell cycle-dependent activity and subcellular localization of Plk1, a recently identified human protein kinase with extensive sequence similarity to both Drosophila polo and S. cerevisiae Cdc5p. With the aid of recombinant baculoviruses, we have established a reliable in vitro assay for Plk1 kinase activity. We show that the activity of human Plk1 is cell cycle regulated, Plk1 activity being low during interphase but high during mitosis. We further show, by immunofluorescent confocal laser scanning microscopy, that human Plk1 binds to components of the mitotic spindle at all stages of mitosis, but undergoes a striking redistribution as cells progress from metaphase to anaphase. Specifically, Plk1 associates with spindle poles up to metaphase, but relocalizes to the equatorial plane, where spindle microtubules overlap (the midzone), as cells go through anaphase. These results indicate that the association of Plk1 with the spindle is highly dynamic and that Plk1 may function at multiple stages of mitotic progression. Taken together, our data strengthen the notion that human Plk1 may represent a functional homolog of polo and Cdc5p, and they suggest that this kinase plays an important role in the dynamic function of the mitotic spindle during chromosome segregation.

Funding

This work was supported by a grant from the Swiss National Science Foundation to E. A. Nigg (31-33615.92). R. M. Golsteyn and A. Fry acknowledge support by fellowships from the Alberta Heritage Foundation for Medical Research, and The Royal Society, respectively. K. Mundt is a recipient of a Swiss Institute for Experimental Cancer Research predoctoral fellowship

History

Citation

Journal of Cell Biology, 1995, 129 (6), pp. 1617-1628

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/MBSP Non-Medical Departments/Molecular & Cell Biology

Version

  • VoR (Version of Record)

Published in

Journal of Cell Biology

Publisher

Rockefeller University Press

issn

0021-9525

eissn

1540-8140

Available date

2016-12-15

Publisher version

http://jcb.rupress.org/content/129/6/1617

Language

en