July 12th (Fri) Seminar at Hokkaido University

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

Prof. Satoshi Sawai, 

Graduate School of Arts and Sciences, University
of Tokyo   (Singularity Biology A03)

[Date] 10:00-18:00 July 12th (Fri)
[Venue] RIES (Hokkaido University), Northern Campus Building No.5, Seminar room 1-2
Access: https://www.es.hokudai.ac.jp/english/about/

[Language] English


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.