“Binding and linkage between complex orders – an example from cellular slime mold.“

澤井哲教授　　東京大学　大学院総合文化研究科広域科学専攻
（シンギュラリティ生物学　公募班A03）

日時： 7月12日（金）
場所： 電子科学研究所（総合研究棟5号館）　セミナー室1-2、10:00-18:00
http://www.es.hokudai.ac.jp/about/　学内バスも15分間隔で北大正門からでて
います。
言語：英語

A profound example of cellular self-organization can be seen in the 
social amoebae Dictyostelium discoideum, where populations of 
undifferentiated cells forms multicellular structure through collective 
migratory behavior.  Increase in extracellular chemoattractant cAMP, 
through membrane-bound receptor signaling invokes a transient rise in 
cytosolic cAMP that is secreted to excite other cells.  The resulting 
synchronized oscillations and waves of extracellular cAMP act as a cue 
to direct aggregation of several thousand cells into a single mound 
where cells differentiate, migrate and sort out to form a multicellular 
structure.  Based on live cell imaging and mathematical analysis, our 
lab has brought to light dynamical understanding of the key steps that 
dictate the self-organizing behavior.   In this talk, I will go over 1) 
how the oscillations of cAMP begin, 2) how it is realized robustly under 
various conditions, 3) how cells ‘perceive’ the cAMP wave for 
migration, and how 4) local cell-cell contact signal work together with 
the diffusible cAMP signal during pattern formation in the multicellular 
mound. 

1.  T. Fujimori, A. Nakajima, N. Shimada, S. Sawai (2019) Tissue self-
organization based on collective cell migration by contact activation of 
locomotion and chemotaxis. Proc. Natl. Acad. Sci. USA  116, 4291-4296.
2.  K. Kamino, Y. Kondo, A. Nakajima, M. Honda-Kitahara, K. Kaneko, S. 
Sawai (2017) Fold-change detection and scale-invariance of cell-cell 
signaling in social amoeba. Proc. Natl. Acad. Sci. USA 114, E4149-E4157.
3.  A. Nakajima, S. Ishihara, D. Imoto and S. Sawai (2014) Rectified 
directional sensing in long-range cell migration. Nat. Commun. 5, 5367.
4.  D. Taniguchi‡, S. Ishihara‡, T. Oonuki, M. Honda-Kitahara, K. 
Kaneko and S. Sawai (2013) Phase geometries of two-dimensional excitable 
waves govern self-organized morphodynamics of amoeboid cells.  Proc. 
Natl. Acad. Sci. USA. 110, 5016-5021. (‡ Equal contribution)
5.  T. Gregor, K. Fujimoto, N. Masaki and S. Sawai (2010) The onset of 
collective behavior in social amoebae. Science 328, 1021-1025.
6.  S. Sawai, P.T. Thomason and E.C. Cox  (2005) An autoregulatory 
circuit for long-range self-organization in Dictyostelium cell 
populations. Nature 433, 323-326.