Dissecting “Fluctuation” and “Mechanical communication” in biological systems

Dissecting “Fluctuation” and “Mechanical communication” in biological systems

Group leader:
Mitsuhiro IWAKI, Senior Researcher
/ 岩城光宏 主任研究員


We have developed a high-speed, high-resolution single-molecule detection techniques for motor proteins that contract muscles and make the heart beat, and have revealed the mechanism by which motor molecules function while utilizing fluctuations. Artificial machines adopt a mechanism of using large amounts of energy to block fluctuations because they regard them as noise. However, biological nanomachines such as motor proteins have created a mechanism that coexists with fluctuations, making it possible to perform movement and information processing with extremely small amounts of energy. We have also revealed that mechanical force is used as a means of information communication for nanomachines to control fluctuations and function cooperatively with each other. Therefore, we are advancing research on the development of technologies for visualizing “fluctuations” and “mechanical force” that occur in biological nanomachine systems and inside cells, as well as studying information processing mechanisms that are driven by ultra-low energy consumption.


Visualizing mechanical communication in biological system


Figure 1. Illustration of our original DNA force sensor "Nanospring" (Iwaki et al., Nat.Commun.,2016; Matsubara et al., ACS Nano,2023).


Biological systems perform parallel information processing while converting electrical signals, molecular signals, and mechanical signals into each other. Among them, mechanical signals involve temporal and spatial fluctuations in the magnitude and direction of mechanical force, but there is still a lack of tools for visualizing them because they have no physical entity as a molecule. We have developed various force sensors using DNA as a material and visualized mechanical forces that work between biomolecules and cells by converting them into fluorescent signals. Biological nanomachine systems and cells use ultra-sensitive sensors (mechanosensors) that detect mechanical signals of the same magnitude as mechanical noise due to thermal fluctuations to process information and respond, but their mechanisms are still largely unknown. We are aiming to understand the mechanism and engineering application by combining our original tools with existing biophysical tools.


Designing and analyzing of Brownian machine assembly


Figure 2. Illustration of our artificial nano-muscle (Fujita et al., Commun.Biol.,2019).


We will design a system consisting of biological nanomachines that function using fluctuations and develop a technique for super-resolution imaging of individual operations within the system. Although the operation analysis of the entire system has been performed so far, there has been no example of visualizing how individual nanomachines fluctuate and communicate with each other while cooperating inside. By simultaneously measuring the movements of multiple nanomachines at a temporal and spatial resolution that can observe fluctuations existing inside the system, and combining them with simulation and information physics, we will create a new concept of a noise-robust system that is driven by ultra-low energy consumption.