BubR1 and CENP-E have antagonistic effects upon the stability of microtubule-kinetochore attachments in Drosophila S2 cell mitosis. 2007

André F Maia, and Carla S Lopes, and Claudio E Sunkel
IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.

The spindle assembly checkpoint ensures the fidelity of chromosome segregation at each cell division cycle. Previous reports have indicated that in higher eukaryotes checkpoint proteins, such as BubR1, are also implicated in chromosome congression, more specifically that BubR1 regulates chromosome-spindle attachments. Also, several studies have shown that BubR1 interacts with the microtubule motor protein CENP-E. Whether this association contributes to the regulation of chromosome-spindle attachments is not yet known. Accordingly, we performed a detailed analysis of microtubule-kinetochore interactions after depletion of BubR1 and the Drosophila CENP-E homolog, CENP-meta by RNAi. We find that depletion of BubR1 affects mitosis very differently from depletion of CENP-meta. While BubR1-depleted cells exit mitosis prematurely due to loss of SAC activity, CENP-meta-depleted cells accumulate in prometaphase and do not exit mitosis after spindle damage. Also, in contrast to cells depleted for CENP-meta, cells depleted for BubR1 very rarely reach full metaphase alignment even if arrested in mitosis with the proteasome inhibitor MG132. More importantly, we show for the first time that BubR1-depleted cells contain a high frequency of either monoriented or fully unattached chromosomes while most CENP-meta dsRNAi-treated cells have chromosomes attached to spindle microtubules. Moreover, simultaneous depletion of both proteins reveals that absence of CENP-meta is able to partially rescue the unattached chromosome phenotype observed after BubR1 depletion. These results strongly suggest that while BubR1 is required to promote stable microtubule kinetochore attachment, CENP-E appears to be required to destabilize kinetochore attachment. Overall our results suggest that activation of the mechanism that corrects inappropriate kinetochore attachment requires the antagonistic effects of BubR1 and CENP-E.

UI MeSH Term Description Entries
D007976 Leupeptins A group of acylated oligopeptides produced by Actinomycetes that function as protease inhibitors. They have been known to inhibit to varying degrees trypsin, plasmin, KALLIKREINS, papain and the cathepsins.
D008677 Metaphase The phase of cell nucleus division following PROMETAPHASE, in which the CHROMOSOMES line up across the equatorial plane of the SPINDLE APPARATUS prior to separation.
D008856 Microscopy, Fluorescence Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye. Fluorescence Microscopy,Immunofluorescence Microscopy,Microscopy, Immunofluorescence,Fluorescence Microscopies,Immunofluorescence Microscopies,Microscopies, Fluorescence,Microscopies, Immunofluorescence
D008869 Microtubule-Associated Proteins High molecular weight proteins found in the MICROTUBULES of the cytoskeletal system. Under certain conditions they are required for TUBULIN assembly into the microtubules and stabilize the assembled microtubules. Ensconsin,Epithelial MAP, 115 kDa,Epithelial Microtubule-Associate Protein, 115 kDa,MAP4,Microtubule Associated Protein,Microtubule Associated Protein 4,Microtubule Associated Protein 7,Microtubule-Associated Protein,Microtubule-Associated Protein 7,E-MAP-115,MAP1 Microtubule-Associated Protein,MAP2 Microtubule-Associated Protein,MAP3 Microtubule-Associated Protein,Microtubule Associated Proteins,Microtubule-Associated Protein 1,Microtubule-Associated Protein 2,Microtubule-Associated Protein 3,7, Microtubule-Associated Protein,Associated Protein, Microtubule,E MAP 115,Epithelial Microtubule Associate Protein, 115 kDa,MAP1 Microtubule Associated Protein,MAP2 Microtubule Associated Protein,MAP3 Microtubule Associated Protein,Microtubule Associated Protein 1,Microtubule Associated Protein 2,Microtubule Associated Protein 3,Microtubule-Associated Protein, MAP1,Microtubule-Associated Protein, MAP2,Microtubule-Associated Protein, MAP3,Protein 7, Microtubule-Associated,Protein, Microtubule Associated,Protein, Microtubule-Associated
D008870 Microtubules Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS. Microtubule
D008938 Mitosis A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species. M Phase, Mitotic,Mitotic M Phase,M Phases, Mitotic,Mitoses,Mitotic M Phases,Phase, Mitotic M,Phases, Mitotic M
D008941 Spindle Apparatus A microtubule structure that forms during CELL DIVISION. It consists of two SPINDLE POLES, and sets of MICROTUBULES that may include the astral microtubules, the polar microtubules, and the kinetochore microtubules. Mitotic Apparatus,Mitotic Spindle Apparatus,Spindle Apparatus, Mitotic,Meiotic Spindle,Meiotic Spindle Apparatus,Mitotic Spindle,Apparatus, Meiotic Spindle,Apparatus, Mitotic,Apparatus, Mitotic Spindle,Apparatus, Spindle,Meiotic Spindles,Mitotic Spindles,Spindle Apparatus, Meiotic,Spindle, Meiotic,Spindle, Mitotic,Spindles, Meiotic,Spindles, Mitotic
D002460 Cell Line Established cell cultures that have the potential to propagate indefinitely. Cell Lines,Line, Cell,Lines, Cell
D002875 Chromosomes In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed) Chromosome
D004331 Drosophila melanogaster A species of fruit fly frequently used in genetics because of the large size of its chromosomes. D. melanogaster,Drosophila melanogasters,melanogaster, Drosophila

Related Publications

André F Maia, and Carla S Lopes, and Claudio E Sunkel
August 2014, Molecular biology of the cell,
André F Maia, and Carla S Lopes, and Claudio E Sunkel
January 2015, Cell cycle (Georgetown, Tex.),
André F Maia, and Carla S Lopes, and Claudio E Sunkel
September 2020, Essays in biochemistry,
André F Maia, and Carla S Lopes, and Claudio E Sunkel
January 2015, Nature reviews. Molecular cell biology,
André F Maia, and Carla S Lopes, and Claudio E Sunkel
July 2014, Biophysical journal,
André F Maia, and Carla S Lopes, and Claudio E Sunkel
October 2014, Journal of cell science,
André F Maia, and Carla S Lopes, and Claudio E Sunkel
May 2020, The Journal of cell biology,
André F Maia, and Carla S Lopes, and Claudio E Sunkel
March 2004, Journal of cell science,
André F Maia, and Carla S Lopes, and Claudio E Sunkel
April 2018, The Journal of biological chemistry,
André F Maia, and Carla S Lopes, and Claudio E Sunkel
July 2018, The Journal of biological chemistry,
Copied contents to your clipboard!