Using default constraints of the spindle assembly checkpoint to estimate the associated chemical rates
نویسندگان
چکیده
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.
منابع مشابه
Reverse Engineering of the Spindle Assembly Checkpoint
The Spindle Assembly Checkpoint (SAC) is an intracellular mechanism that ensures proper chromosome segregation. By inhibiting Cdc20, a co-factor of the Anaphase Promoting Complex (APC), the checkpoint arrests the cell cycle until all chromosomes are properly attached to the mitotic spindle. Inhibition of Cdc20 is mediated by a conserved network of interacting proteins. The individual functions ...
متن کاملDiverse functions of spindle assembly checkpoint genes in Saccharomyces cerevisiae.
The spindle assembly checkpoint regulates the metaphase-to-anaphase transition from yeast to humans. We examined the genetic interactions with four spindle assembly checkpoint genes to identify nonessential genes involved in chromosome segregation, to identify the individual roles of the spindle assembly checkpoint genes within the checkpoint, and to reveal potential complexity that may exist. ...
متن کاملCell shape impacts on the positioning of the mitotic spindle with respect to the substratum
All known mechanisms of mitotic spindle orientation rely on astral microtubules. We report that even in the absence of astral microtubules, metaphase spindles in MDCK and HeLa cells are not randomly positioned along their x-z dimension, but preferentially adopt shallow β angles between spindle pole axis and substratum. The nonrandom spindle positioning is due to constraints imposed by the cell ...
متن کاملInvestigating The Asymmetric Effects of Macroeconomic Variables on Bank Default Rates During High and Low Default Periods
In recent decades, the high rate of inflation has been one of the concerns of Iran's economy, and one of the main causes of inflation has been the imbalance of banks. The level of non-current claims of banks has been increasing due to the economic recession, credit facilities and the lack of optimal allocation of facilities, and therefore it has unbalanced the balance sheets of banks, hence the...
متن کاملAssociation of spindle assembly checkpoint component XMAD2 with unattached kinetochores.
The spindle assembly checkpoint delays anaphase until all chromosomes are attached to a mitotic spindle. The mad (mitotic arrest-deficient) and bub (budding uninhibited by benzimidazole) mutants of budding yeast lack this checkpoint and fail to arrest the cell cycle when microtubules are depolymerized. A frog homolog of MAD2 (XMAD2) was isolated and found to play an essential role in the spindl...
متن کامل