dictyNews
Electronic Edition
Volume 33, number 11
October 30, 2009

Please submit abstracts of your papers as soon as they have been
accepted for publication by sending them to dicty@northwestern.edu
or by using the form at
http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit.

Back issues of dictyNews, the Dicty Reference database and other
useful information is available at dictyBase - http://dictybase.org.

Follow dictyBase now on twitter:
http://twitter.com/dictybase

=========
Abstracts
=========


Propagating waves separate two states of actin organization in living cells

Britta Schroth-Diez,1 Silke Gerwig,1 Mary Ecke,2 Reiner Hegerl,2
Stefan Diez,1 and Günther Gerisch2

1Max-Planck-Institut für Molekulare Zellbiologie und Genetik, 
Pfotenhauerstrasse 108, D-01307 Dresden, Germany
2Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 
D-82152 Martinsried, Germany


HFSP Journal, in press [DOI: 10.2976/1.3239407]

Propagating actin waves are dynamic supramolecular structures formed by the 
self-assembly of proteins within living cells. They are built from actin filaments 
together with single-headed myosin, the Arp2/3 complex, and coronin in a 
defined three-dimensional order. The function of these waves in structuring the 
cell cortex is studied on the substrate-attached surface of Dictyostelium cells 
by the use of total internal reflection fluorescence (TIRF) microscopy. Actin 
waves separate two areas of the cell cortex from each other, which are 
distinguished by the arrangement of actin filaments. The Arp2/3 complex 
dominates in the area enclosed by a wave, where it has the capacity of 
building dendritic structures, while the proteins prevailing in the external area, 
cortexillin I and myosin-II, bundle actin filaments and arrange them in 
antiparallel direction. Wave propagation is accompanied by transitions in the 
state of actin with a preferential period of 5 min. Wave generation is preceded 
by local fluctuations in actin assembly, some of the nuclei of polymerized actin 
emanating from clathrin-coated structures, others emerging independently. 
The dynamics of phase transitions has been analyzed to provide a basis for 
modeling the nonlinear interactions that produce spatio-temporal patterns in 
the actin system of living cells. 

Submitted by Günther Gerisch [gerisch@biochem.mpg.de]
==============================================================
[End dictyNews, volume 33, number 11]