Department of Physics, Emory University, Atlanta, GA 30322, USA.
Phys Biol. 2013 Jun;10(3):035008. doi: 10.1088/1478-3975/10/3/035008. Epub 2013 Jun 4.
Cells often have tens of thousands of receptors, even though only a few activated receptors can trigger full cellular responses. Reasons for the overabundance of receptors remain unclear. We suggest that, under certain conditions, the large number of receptors can result in a competition among receptors to be the first to activate the cell. The competition decreases the variability of the time to cellular activation, and hence results in a more synchronous activation of cells. We argue that, in simple models, this variability reduction does not necessarily interfere with the receptor specificity to ligands achieved by the kinetic proofreading mechanism. Thus cells can be activated accurately in time and specifically to certain signals. We predict the minimum number of receptors needed to reduce the coefficient of variation for the time to activation following binding of a specific ligand. Furthermore, we predict the maximum number of receptors so that the kinetic proofreading mechanism still can improve the specificity of the activation. These predictions fall in line with experimentally reported receptor numbers for multiple systems.
细胞通常有数千个受体，尽管只有少数激活的受体可以引发完整的细胞反应。受体过剩的原因尚不清楚。我们认为，在某些条件下，大量的受体可能导致受体之间的竞争，以成为第一个激活细胞的受体。这种竞争降低了细胞激活时间的可变性，从而导致细胞更同步地激活。我们认为，在简单的模型中，这种可变性的降低不一定会干扰通过动力学校验机制实现的受体对配体的特异性。因此，细胞可以在时间上准确地并特异性地对特定信号进行激活。我们预测了减少特定配体结合后激活时间变化系数所需的最小受体数量。此外，我们还预测了最大受体数量，以便动力学校验机制仍然可以提高激活的特异性。这些预测与多个系统的实验报告的受体数量相符。
