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Using default constraints of the spindle assembly checkpoint to estimate the associated chemical rates.

Dao Duc K, Holcman D - BMC Biophys (2012)

Bottom Line: Our purpose is to use these opposed constraints to estimate the associated chemical rates.We compute the probability for no APC/C activation before time t, the distribution of Cdc20 at equilibrium and the mean time to complete APC/C activation after all chromosomes are attached.By studying Cdc20 inhibition and the activation time, we obtain a range for the main chemical reaction rates regulating the spindle assembly checkpoint and transition to anaphase.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Biology (IBENS), Group of Computational Biology and Applied Mathematics, Ecole Normale Supérieure, 46 rue d'Ulm 75005 Paris, France. holcman@ens.fr.

ABSTRACT

Unlabelled: :

Background: Default activation of the spindle assembly checkpoint provides severe constraints on the underlying biochemical activation rates: on one hand, the cell cannot divide before all chromosomes are aligned, but on the other hand, when they are ready, the separation is quite fast, lasting a few minutes. Our purpose is to use these opposed constraints to estimate the associated chemical rates.

Results: To analyze the above constraints, we develop a markovian model to describe the dynamics of Cdc20 molecules. We compute the probability for no APC/C activation before time t, the distribution of Cdc20 at equilibrium and the mean time to complete APC/C activation after all chromosomes are attached.

Conclusions: By studying Cdc20 inhibition and the activation time, we obtain a range for the main chemical reaction rates regulating the spindle assembly checkpoint and transition to anaphase.

No MeSH data available.


Related in: MedlinePlus

The probability P for no activation during the SAC is represented as a function of the time and the rates λ and k-1. A :We plot P(t) as a function of time for different values of λ and k-1 = 1. B: as a function of time for different values of k-1 and λ = 0.1. C: at time t = 1200s as a function of λ and k-1. The parameters are given in table 1.
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Figure 3: The probability P for no activation during the SAC is represented as a function of the time and the rates λ and k-1. A :We plot P(t) as a function of time for different values of λ and k-1 = 1. B: as a function of time for different values of k-1 and λ = 0.1. C: at time t = 1200s as a function of λ and k-1. The parameters are given in table 1.

Mentions: P is a decreasing function of time, and remains constant for λ = 0 and μ = 0. In figure 3, we plot P as a function of time for different values of λ and k-1, and as a function of λ and k-1 at a given time. It is a decreasing function of λ (increasing the Cdc20 production rate decreases the probability of activation) and a decreasing function of k-1 (increasing the inhibition of Cdc20 increases the probability for no activation).


Using default constraints of the spindle assembly checkpoint to estimate the associated chemical rates.

Dao Duc K, Holcman D - BMC Biophys (2012)

The probability P for no activation during the SAC is represented as a function of the time and the rates λ and k-1. A :We plot P(t) as a function of time for different values of λ and k-1 = 1. B: as a function of time for different values of k-1 and λ = 0.1. C: at time t = 1200s as a function of λ and k-1. The parameters are given in table 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368725&req=5

Figure 3: The probability P for no activation during the SAC is represented as a function of the time and the rates λ and k-1. A :We plot P(t) as a function of time for different values of λ and k-1 = 1. B: as a function of time for different values of k-1 and λ = 0.1. C: at time t = 1200s as a function of λ and k-1. The parameters are given in table 1.
Mentions: P is a decreasing function of time, and remains constant for λ = 0 and μ = 0. In figure 3, we plot P as a function of time for different values of λ and k-1, and as a function of λ and k-1 at a given time. It is a decreasing function of λ (increasing the Cdc20 production rate decreases the probability of activation) and a decreasing function of k-1 (increasing the inhibition of Cdc20 increases the probability for no activation).

Bottom Line: Our purpose is to use these opposed constraints to estimate the associated chemical rates.We compute the probability for no APC/C activation before time t, the distribution of Cdc20 at equilibrium and the mean time to complete APC/C activation after all chromosomes are attached.By studying Cdc20 inhibition and the activation time, we obtain a range for the main chemical reaction rates regulating the spindle assembly checkpoint and transition to anaphase.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Biology (IBENS), Group of Computational Biology and Applied Mathematics, Ecole Normale Supérieure, 46 rue d'Ulm 75005 Paris, France. holcman@ens.fr.

ABSTRACT

Unlabelled: :

Background: Default activation of the spindle assembly checkpoint provides severe constraints on the underlying biochemical activation rates: on one hand, the cell cannot divide before all chromosomes are aligned, but on the other hand, when they are ready, the separation is quite fast, lasting a few minutes. Our purpose is to use these opposed constraints to estimate the associated chemical rates.

Results: To analyze the above constraints, we develop a markovian model to describe the dynamics of Cdc20 molecules. We compute the probability for no APC/C activation before time t, the distribution of Cdc20 at equilibrium and the mean time to complete APC/C activation after all chromosomes are attached.

Conclusions: By studying Cdc20 inhibition and the activation time, we obtain a range for the main chemical reaction rates regulating the spindle assembly checkpoint and transition to anaphase.

No MeSH data available.


Related in: MedlinePlus