![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
|
|
|
|
|
||
A more recent version of this article appeared on May 1, 2002
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Submitted on September 4, 2001
Revised on January 15, 2002
Accepted on January 24, 2002
1 Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
* Corresponding author. E-mail address: rc70{at}cornell.edu.
The spindle checkpoint prevents anaphase from occurring until all chromosomes have attached properly to the mitotic spindle. The checkpoint components Mad1 and Mad2 associate with unattached kinetochores and are likely involved in triggering the checkpoint. We now demonstrate that in Xenopus egg extracts Mad1 and Mad2 form a stable complex, while a fraction of Mad2 molecules are not bound to Mad1. The checkpoint establishment and maintenance are lost upon titrating out free Mad2 with an excess of Mad1 or a truncated Mad1 (amino acids 326-718, Mad1C) that contains the Mad2-binding region. Mad1N (amino acids 1-445) that binds kinetochores, but not Mad2, reduces Mad1 and Mad2 at kinetochores and abolishes checkpoint maintenance. Furthermore, the association between Mad2 and Cdc20, the activator for the anaphase-promoting complex (APC), is enhanced under checkpoint-active condition compared to that at metaphase. Immunodepletion analysis shows that the Mad1-free Mad2 protein is unable to bind Cdc20, consistent with the model that kinetochore-localization of Mad2 facilitates the formation of Mad2-Cdc20 complex. This study demonstrates that the ratio between Mad1 and Mad2 is critical for maintaining a pool of Mad1-free Mad2 that is necessary for the spindle checkpoint. We propose that Mad2 may become activated and dissociated from Mad1 at kinetochores and is replenished by the pool of Mad1-free Mad2.
This article has been cited by other articles:
|
|
 |
|
  K. M.-F. Sze, Y.-P. Ching, D.-Y. Jin, and I. O.-L. Ng Role of a Novel Splice Variant of Mitotic Arrest Deficient 1 (MAD1), MAD1{beta}, in Mitotic Checkpoint Control in Liver Cancer Cancer Res., November 15, 2008; 68(22): 9194 - 9201. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. M. Bentley, G. Normand, J. Hoyt, and R. W. King Distinct Sequence Elements of Cyclin B1 Promote Localization to Chromatin, Centrosomes, and Kinetochores during Mitosis Mol. Biol. Cell, December 1, 2007; 18(12): 4847 - 4858. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Yu Structural activation of Mad2 in the mitotic spindle checkpoint: the two-state Mad2 model versus the Mad2 template model J. Cell Biol., April 24, 2006; 173(2): 153 - 157. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. A. Daniel, B. E. Keyes, Y. P. Y. Ng, C. O. Freeman, and D. J. Burke Diverse Functions of Spindle Assembly Checkpoint Genes in Saccharomyces cerevisiae Genetics, January 1, 2006; 172(1): 53 - 65. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Kastenmayer, M. S. Lee, A. L. Hong, F. A. Spencer, and M. A. Basrai The C-Terminal Half of Saccharomyces cerevisiae Mad1p Mediates Spindle Checkpoint Function, Chromosome Transmission Fidelity and CEN Association Genetics, June 1, 2005; 170(2): 509 - 517. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Zhang, M. Li, W. Ma, Y. Hou, Y.-H. Li, S.-W. Li, Q.-Y. Sun, and W.-H. Wang Localization of Mitotic Arrest Deficient 1 (MAD1) in Mouse Oocytes During the First Meiosis and Its Functions as a Spindle Checkpoint Protein Biol Reprod, January 1, 2005; 72(1): 58 - 68. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Pati, B. R. Haddad, A. Haegele, H. Thompson, F. S. Kittrell, A. Shepard, C. Montagna, N. Zhang, G. Ge, S. K. Otta, et al. Hormone-Induced Chromosomal Instability in p53-Null Mammary Epithelium Cancer Res., August 15, 2004; 64(16): 5608 - 5616. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Pan and R.-H. Chen Spindle checkpoint regulates Cdc20p stability in Saccharomyces cerevisiae Genes & Dev., June 15, 2004; 18(12): 1439 - 1451. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. J. Tunquist, P. A. Eyers, L. G. Chen, A. L. Lewellyn, and J. L. Maller Spindle checkpoint proteins Mad1 and Mad2 are required for cytostatic factor-mediated metaphase arrest J. Cell Biol., December 22, 2003; 163(6): 1231 - 1242. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L.-H. Yih and T.-C. Lee Induction of C-Anaphase and Diplochromosome through Dysregulation of Spindle Assembly Checkpoint by Sodium Arsenite in Human Fibroblasts Cancer Res., October 15, 2003; 63(20): 6680 - 6688. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. C. S. Chun and D.-Y. Jin Transcriptional Regulation of Mitotic Checkpoint Gene MAD1 by p53 J. Biol. Chem., September 26, 2003; 278(39): 37439 - 37450. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. J. Tunquist and J. L. Maller Under arrest: cytostatic factor (CSF)-mediated metaphase arrest in vertebrate eggs Genes & Dev., March 15, 2003; 17(6): 683 - 710. [Full Text] [PDF]
|
|
|
|
 |
|
 L. Campbell and K. G. Hardwick Analysis of Bub3 spindle checkpoint function in Xenopus egg extracts J. Cell Sci., February 15, 2003; 116(4): 617 - 628. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Iouk, O. Kerscher, R. J. Scott, M. A. Basrai, and R. W. Wozniak The yeast nuclear pore complex functionally interacts with components of the spindle assembly checkpoint J. Cell Biol., December 9, 2002; 159(5): 807 - 819. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. B. Shannon, J. C. Canman, and E. D. Salmon Mad2 and BubR1 Function in a Single Checkpoint Pathway that Responds to a Loss of Tension Mol. Biol. Cell, October 1, 2002; 13(10): 3706 - 3719. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R.-H. Chen BubR1 is essential for kinetochore localization of other spindle checkpoint proteins and its phosphorylation requires Mad1 J. Cell Biol., August 5, 2002; 158(3): 487 - 496. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Canman, N. Sharma, A. Straight, K. B. Shannon, G. Fang, and E. D. Salmon Anaphase onset does not require the microtubule-dependent depletion of kinetochore and centromere-binding proteins J. Cell Sci., January 10, 2002; 115(19): 3787 - 3795. [Abstract] [Full Text] [PDF]
|
|
