arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1504.07700q-bio.QMq-bio.SC
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受体记忆与配体再结合的相互作用

Interplay of receptor memory and ligand rebinding

Thorsten Prüstel, Martin Meier-Schellersheim

摘要:

解离后紧密接近的分子相互作用伴侣的快速再结合导致解离和缔合动力学,其可以与基于本体反应模型的预测有很大不同。这种效应的原因可以追溯到配体的再结合时间概率密度函数的非马尔可夫特征,反映了这样一个事实,即在一定的时间跨度内,配体仍然“记住”它以前结合的受体。在这份手稿中,我们探讨的假设,初始绑定和连续重新绑定产生的债券寿命密度,是非马尔可夫以及后果。我们研究了两个非马尔可夫等待时间概率密度的综合效应,并表明即使在很短的时间内,被占用受体的分数的衰减偏离指数。在很长一段时间内,解离比指数慢,稳态结合受体部分的命运严重依赖于相对于重新结合时间密度的偏离程度,从马尔可夫极限:被占据的受体的群体可以完全衰减或分别为小的和强的偏差假设非零值。此外,我们指出了分数阶微积分所发挥的重要作用,并表明,短期和长期的动态被占领的受体可以自然地表示,以及很容易获得的分数阶微分方程涉及的黎曼-刘维导数。我们的分析表明,细胞可以利用受体记忆作为机制,动态地扩大对给定信号的潜在响应模式的范围。

英文摘要:

Rapid rebinding of molecular interaction partners that are in close proximity after dissociation leads to a dissociation and association kinetics that can profoundly differ from predictions based on bulk reaction models. The cause of this effect can be traced back to the non-Markovian character of the ligand's rebinding time probability density function, reflecting the fact that, for a certain time span, the ligand still 'remembers' the receptor it was bound to previously. In this manuscript, we explore the consequences of the hypothesis that initial binding and consecutive rebinding give rise to a bond lifetime density that is non-Markovian as well. We study the combined effect of the two non-Markovian waiting time probability densities and show that even for very short times the decay of the fraction of occupied receptors deviates from an exponential. For long times, dissociation is slower than an exponential and the fate of the the steady-state bound receptor fraction critically depends on the extent of the deviation, relative to the rebinding time density, from the Markovian limit: The population of occupied receptors may either decay completely or assume a non-vanishing value for small and strong deviations, respectively. Furthermore, we point out the important role played by fractional calculus and demonstrate that the short- and long-time dynamics of the occupied receptors can be naturally expressed as well as easily obtained in terms of fractional differential equations involving the Riemann-Liouville derivative. Our analysis shows that cells may exploit receptor memory as mechanism to dynamically widen the range of potential response-patterns to a given signal.

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