August 30, 2023
Keio University
Tokyo University of Science
A research group led by Senior Assistant Professor Eiji Yamamoto and Associate Professor Mayu Muramatsu of the Faculty of Science and Technology at Keio University; Associate Professor Takuma Akimoto of the Faculty of Science and Engineering at Tokyo University of Science; Professor Emeritus Mark S. P. Sansom of the University of Oxford; and Professor Ralf Metzler of the University of Potsdam has developed a method for mesoscale (centered on sizes of 5–100 nm) simulations of cell membranes where the liquid-ordered (Lo) and liquid-disordered (Ld) phases coexist. They have clarified the effects of cell membrane heterogeneity on protein diffusion and localization.
In systems containing two or more types of molecules, a heterogeneous state can emerge where the molecules do not mix and instead separate into phases (domains). Phase separation is a phenomenon observed in various fields, including biology, physics, and engineering. Understanding the principles of how molecules diffuse in heterogeneous fields and how their localization is controlled is crucial for system control and design. In this study, the research group developed a new mesoscale computational method and simulated the diffusion behavior of proteins in cell membranes phase-separated into Lo and Ld phases on a scale of tens of milliseconds. This time and spatial scale corresponds to the mesoscale, where a gap has existed between the observable spatiotemporal domains of computation and experiment. With the developed computational method, they have succeeded for the first time in simulating molecular diffusion at the mesoscale. The results showed that the localization of proteins in the Lo phase is determined by the difference in molecular diffusivity between the Lo and Ld phases (inter-domain), the domain preference of the molecules, and the molecular concentration. They also clarified the impact of diffusing proteins on the size and shape of the domains.
The results of this research were published in the American scientific journal PNAS Nexus on August 3, 2023.
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