KAIST Vision Hall
Important On-campus Websites
Personal Information Policy
Main Campus (Daejeon)
Seoul Campus (Seoul)
Munji Campus (Daejeon)
Dogok Campus (Seoul)
How to get to KAIST
Giving to KAIST
Excellence in KAIST
Use of Gift
Make a Gift
College of Natural Sciences
College of Life Science and Bio Engineering
College of Engineering
College of Liberal Arts and Convergence Science
College of Business
School of Transdisciplinary Studies
General Studies Requirements
Education Support Program
Int'l Exchange Programs
International Scholar and Student Service Team
Center for Excellence in Learning and Teaching
Research Areas and Main Research Programs
Person in Charge by Research Area
Common Utilized Equipment
Office of Univ. Industry Coop.
World Economic Forum
KAIST Annual R&D Report
Student Health Insurance Association
Cultural Event Info.
Satisfaction survey of food&beverage Enterprise inside Campus
Day Care Center
Student Clubs and Activities
Undergraduate Student Clubs
Graduate Student Clubs
Center For Ethics And Human Rights
Intl’ Student Identity Card (ISIC)
KAIST in Media
International Scholar and Student Services
A Mathematical Model Reveals Long-Distance Cell Communication Mechanism
How can tens of thousands of people in a large football stadium all clap together with the same beat even though they can only hear the people near them clapping?
A combination of a partial differential equation and a synthetic circuit in microbes answers this question. An interdisciplinary collaborative team of Professor Jae Kyoung Kim at KAIST, Professor Krešimir Josić at the University of Houston, and Professor Matt Bennett at Rice University has identified how a large community can communicate with each other almost simultaneously even with very short distance signaling. The research was reported at Nature Chemical Biology.
Cells often communicate using signaling molecules, which can travel only a short distance. Nevertheless, the cells can also communicate over large distances to spur collective action. The team revealed a cell communication mechanism that quickly forms a network of local interactions to spur collective action, even in large communities.
The research team used an engineered transcriptional circuit of combined positive and negative feedback loops in E. coli, which can periodically release two types of signaling molecules: activator and repressor. As the signaling molecules travel over a short distance, cells can only talk to their nearest neighbors. However, cell communities synchronize oscillatory gene expression in spatially extended systems as long as the transcriptional circuit contains a positive feedback loop for the activator.
Professor Kim said that analyzing and understanding such high-dimensional dynamics was extremely difficult. He explained, “That’s why we used high-dimensional partial differential equation to describe the system based on the interactions among various types of molecules.” Surprisingly, the mathematical model accurately simulates the synthesis of the signaling molecules in the cell and their spatial diffusion throughout the chamber and their effect on neighboring cells.
The team simplified the high-dimensional system into a one-dimensional orbit, noting that the system repeats periodically. This allowed them to discover that cells can make one voice when they lowered their own voice and listened to the others. “It turns out the positive feedback loop reduces the distance between moving points and finally makes them move all together. That’s why you clap louder when you hear applause from nearby neighbors and everyone eventually claps together at almost the same time,” said Professor Kim.
Professor Kim added, “Math is a powerful as it simplifies complex thing so that we can find an essential underlying property. This finding would not have been possible without the simplification of complex systems using mathematics."
The National Institutes of Health, the National Science Foundation, the Robert A. Welch Foundation, the Hamill Foundation, the National Research Foundation of Korea, and the T.J. Park Science Fellowship of POSCO supported the research.
(Figure: Complex molecular interactions among microbial consortia is simplified as interactions among points on a limit cycle (right).)