Olsman Noah, Goentoro Lea
Department of Computing and Mathematical Sciences, California Institute of Technology, Pasadena, CA 91125;
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
Proc Natl Acad Sci U S A. 2016 Jul 26;113(30):E4423-30. doi: 10.1073/pnas.1601791113. Epub 2016 Jul 7.
Many sensory systems, from vision and hearing in animals to signal transduction in cells, respond to fold changes in signal relative to background. Responding to fold change requires that the system senses signal on a logarithmic scale, responding identically to a change in signal level from 1 to 3, or from 10 to 30. It is an ongoing search in the field to understand the ways in which a logarithmic sensor can be implemented at the molecular level. In this work, we present evidence that logarithmic sensing can be implemented with a single protein, by means of allosteric regulation. Specifically, we find that mathematical models show that allosteric proteins can respond to stimuli on a logarithmic scale. Next, we present evidence from measurements in the literature that some allosteric proteins do operate in a parameter regime that permits logarithmic sensing. Finally, we present examples suggesting that allosteric proteins are indeed used in this capacity: allosteric proteins play a prominent role in systems where fold-change detection has been proposed. This finding suggests a role as logarithmic sensors for the many allosteric proteins across diverse biological processes.
许多感觉系统，从动物的视觉和听觉到细胞中的信号转导，都会对信号相对于背景的倍数变化做出反应。对倍数变化做出反应要求系统在对数尺度上感知信号，对信号水平从1到3或从10到30的变化做出相同的反应。该领域一直在探索如何在分子水平上实现对数传感器。在这项工作中，我们提供证据表明，通过变构调节，单个蛋白质可以实现对数传感。具体而言，我们发现数学模型表明变构蛋白可以在对数尺度上对刺激做出反应。接下来，我们从文献中的测量结果中提供证据，表明一些变构蛋白确实在允许对数传感的参数范围内发挥作用。最后，我们给出的例子表明变构蛋白确实以这种能力被使用：变构蛋白在提出倍数变化检测的系统中发挥着重要作用。这一发现表明，在各种生物过程中的许多变构蛋白都具有作为对数传感器的作用。
