QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 16, Issue 1, 385-395, January 2005

This Article Full Text Full Text (PDF) All Versions of this Article: E04-07-0558v1 16/1/385    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kadura, S. Articles by Sazer, S. Search for Related Content PubMed PubMed Citation Articles by Kadura, S. Articles by Sazer, S.

The A78V Mutation in the Mad3-like Domain of Schizosaccharomyces pombe Bub1p Perturbs Nuclear Accumulation and Kinetochore Targeting of Bub1p, Bub3p, and Mad3p and Spindle Assembly Checkpoint Function

Sheila Kadura ^*, Xiangwei He  , Vincent Vanoosthuyse , Kevin G. Hardwick , and Shelley Sazer ^*  ||

Verna and Marrs McClean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030; ^* Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030; and Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom

Submitted July 6, 2004; Revised October 19, 2004; Accepted October 21, 2004
Monitoring Editor: Mark Solomon

During mitosis, the spindle assembly checkpoint (SAC) responds to faulty attachments between kinetochores and the mitotic spindle by imposing a metaphase arrest until the defect is corrected, thereby preventing chromosome missegregation. A genetic screen to isolate SAC mutants in fission yeast yielded point mutations in three fission yeast SAC genes: mad1, bub3, and bub1. The bub1-A78V mutant is of particular interest because it produces a wild-type amount of protein that is mutated in the conserved but uncharacterized Mad3-like region of Bub1p. Characterization of mutant cells demonstrates that the alanine at position 78 in the Mad3-like domain of Bub1p is required for: 1) cell cycle arrest induced by SAC activation; 2) kinetochore accumulation of Bub1p in checkpoint-activated cells; 3) recruitment of Bub3p and Mad3p, but not Mad1p, to kinetochores in checkpoint-activated cells; and 4) nuclear accumulation of Bub1p, Bub3p, and Mad3p, but not Mad1p, in cycling cells. Increased targeting of Bub1p-A78V to the nucleus by an exogenous nuclear localization signal does not significantly increase kinetochore localization or SAC function, but GFP fused to the isolated Bub1p Mad 3-like accumulates in the nucleus. These data indicate that Bub1p-A78V is defective in both nuclear accumulation and kinetochore targeting and that a threshold level of nuclear Bub1p is necessary for the nuclear accumulation of Bub3p and Mad3p.

Abbreviations used: SAC, spindle assembly checkpoint; Bub, budding uninhibited by benomyl; Mad, mitotic arrest deficient; NLS, nuclear localization signal; MBC, carbendazim; TBZ, thiabendazole; HU, hydroxyurea; YE, yeast extract; EMM, Edinburgh minimal media.

Present address: Department of Human and Molecular Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030.

^|| Corresponding author. E-mail address: ssazer{at}bcm.tmc.edu.

This article has been cited by other articles:

				S. Saitoh, Y. Kobayashi, Y. Ogiyama, and K. Takahashi Dual Regulation of Mad2 Localization on Kinetochores by Bub1 and Dam1/DASH that Ensure Proper Spindle Interaction Mol. Biol. Cell, September 1, 2008; 19(9): 3885 - 3897. [Abstract] [Full Text] [PDF]

				M. Sczaniecka, A. Feoktistova, K. M. May, J.-S. Chen, J. Blyth, K. L. Gould, and K. G. Hardwick The Spindle Checkpoint Functions of Mad3 and Mad2 Depend on a Mad3 KEN Box-mediated Interaction with Cdc20-Anaphase-promoting Complex (APC/C) J. Biol. Chem., August 22, 2008; 283(34): 23039 - 23047. [Abstract] [Full Text] [PDF]

				Y. Tange and O. Niwa Schizosaccharomyces pombe Bub3 Is Dispensable for Mitotic Arrest Following Perturbed Spindle Formation Genetics, June 1, 2008; 179(2): 785 - 792. [Abstract] [Full Text] [PDF]

				K. Asakawa, K. Kume, M. Kanai, T. Goshima, K. Miyahara, S. Dhut, W. W. Tee, D. Hirata, and T. Toda The V260I Mutation in Fission Yeast {alpha}-Tubulin Atb2 Affects Microtubule Dynamics and EB1-Mal3 Localization and Activates the Bub1 Branch of the Spindle Checkpoint Mol. Biol. Cell, March 1, 2006; 17(3): 1421 - 1435. [Abstract] [Full Text] [PDF]

				M. Umeda, S. Izaddoost, I. Cushman, M. S. Moore, and S. Sazer The Fission Yeast Schizosaccharomyces pombe Has Two Importin-{alpha} Proteins, Imp1p and Cut15p, Which Have Common and Unique Functions in Nucleocytoplasmic Transport and Cell Cycle Progression Genetics, September 1, 2005; 171(1): 7 - 21. [Abstract] [Full Text] [PDF]