The influence of catalysis on Mad2 activation dynamics
Mad2 is a key component of the spindle assembly checkpoint, a safety device ensuring faithful sister chromatid separation in mitosis. The target of Mad 2 is Cdc20, an activator of the anaphase-promoting complex/cyclosome (APC/C). Mad2 binding to Cdc20 is a complex reaction that entails the conformat...
| Main Authors: | , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
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Public Library of Science
2009
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| Subjects: |
| _version_ | 1826270368662290432 |
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| author | Simonetta, M Manzoni, R Mosca, R Mapelli, M Massimiliano, L Vink, M Novak, B Musacchio, A Ciliberto, A |
| author_facet | Simonetta, M Manzoni, R Mosca, R Mapelli, M Massimiliano, L Vink, M Novak, B Musacchio, A Ciliberto, A |
| author_sort | Simonetta, M |
| collection | OXFORD |
| description | Mad2 is a key component of the spindle assembly checkpoint, a safety device ensuring faithful sister chromatid separation in mitosis. The target of Mad 2 is Cdc20, an activator of the anaphase-promoting complex/cyclosome (APC/C). Mad2 binding to Cdc20 is a complex reaction that entails the conformational conversion Mad2 from an open (O-Mad2) to a closed (C-Mad2) conformer. Previously, it has been hypothesized that the conversion of O-Mad2 is accelerated by its conformational dimerization with C-Mad2. This hypothesis, known as the Mad2-template hypothesis, is based on the unproven assumption that the natural conversion of O-Mad2 required to bind Cdc20 is slow. Here, we provide evidence for this fundamental assumption and demonstrate that conformational dimerization of Mad2 accelerates the rate of Mad2 binding to Cdc20. On the basis of our measurements, we developed a set of rate equations that deliver excellent predictions of experimental binding curves under a variety of different conditions. Our results strongly suggest that the interaction of Mad2 with Cdc20 is rate limiting for activation of the spindle checkpoint. Conformational dimerization of Mad2 is essential to accelerate Cdc20 binding, but it does not modify the equilibrium of the Mad2:Cdc20 interaction, i.e., it is purely catalytic. These results surpass previously formulated objections to the Mad2-template model and predict that the release of Mad2 from Cdc20 is an energy-driven process. |
| first_indexed | 2024-03-06T21:39:44Z |
| format | Journal article |
| id | oxford-uuid:477fb2c1-3204-4f94-8de9-52db10dcd6e3 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T21:39:44Z |
| publishDate | 2009 |
| publisher | Public Library of Science |
| record_format | dspace |
| spelling | oxford-uuid:477fb2c1-3204-4f94-8de9-52db10dcd6e32022-03-26T15:20:30ZThe influence of catalysis on Mad2 activation dynamicsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:477fb2c1-3204-4f94-8de9-52db10dcd6e3BiochemistryOncologyEnglishOxford University Research Archive - ValetPublic Library of Science2009Simonetta, MManzoni, RMosca, RMapelli, MMassimiliano, LVink, MNovak, BMusacchio, ACiliberto, AMad2 is a key component of the spindle assembly checkpoint, a safety device ensuring faithful sister chromatid separation in mitosis. The target of Mad 2 is Cdc20, an activator of the anaphase-promoting complex/cyclosome (APC/C). Mad2 binding to Cdc20 is a complex reaction that entails the conformational conversion Mad2 from an open (O-Mad2) to a closed (C-Mad2) conformer. Previously, it has been hypothesized that the conversion of O-Mad2 is accelerated by its conformational dimerization with C-Mad2. This hypothesis, known as the Mad2-template hypothesis, is based on the unproven assumption that the natural conversion of O-Mad2 required to bind Cdc20 is slow. Here, we provide evidence for this fundamental assumption and demonstrate that conformational dimerization of Mad2 accelerates the rate of Mad2 binding to Cdc20. On the basis of our measurements, we developed a set of rate equations that deliver excellent predictions of experimental binding curves under a variety of different conditions. Our results strongly suggest that the interaction of Mad2 with Cdc20 is rate limiting for activation of the spindle checkpoint. Conformational dimerization of Mad2 is essential to accelerate Cdc20 binding, but it does not modify the equilibrium of the Mad2:Cdc20 interaction, i.e., it is purely catalytic. These results surpass previously formulated objections to the Mad2-template model and predict that the release of Mad2 from Cdc20 is an energy-driven process. |
| spellingShingle | Biochemistry Oncology Simonetta, M Manzoni, R Mosca, R Mapelli, M Massimiliano, L Vink, M Novak, B Musacchio, A Ciliberto, A The influence of catalysis on Mad2 activation dynamics |
| title | The influence of catalysis on Mad2 activation dynamics |
| title_full | The influence of catalysis on Mad2 activation dynamics |
| title_fullStr | The influence of catalysis on Mad2 activation dynamics |
| title_full_unstemmed | The influence of catalysis on Mad2 activation dynamics |
| title_short | The influence of catalysis on Mad2 activation dynamics |
| title_sort | influence of catalysis on mad2 activation dynamics |
| topic | Biochemistry Oncology |
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