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dictyNews Volume 38 Number 09
dictyNews
Electronic Edition
Volume 38, number 9
March 30, 2012
Please submit abstracts of your papers as soon as they have been
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or by using the form at
http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit.
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Abstracts
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Cooper RM, Wingreen NS, Cox EC
An excitable cortex and memory model successfully predicts new pseudopod
dynamics.
PLoS One available online http://dx.plos.org/10.1371/journal.pone.0033528
Motile eukaryotic cells migrate with directional persistence by alternating
left and right turns, even in the absence of external cues. For example,
Dictyostelium discoideum cells crawl by extending distinct pseudopods in
an alternating right-left pattern. The mechanisms underlying this zig-zag
behavior, however, remain unknown. Here we propose a new Excitable
Cortex and Memory (EC&M) model for understanding the alternating,
zig-zag extension of pseudopods. Incorporating elements of previous models,
we consider the cell cortex as an excitable system and include global inhibition
of new pseudopods while a pseudopod is active. With the novel hypothesis
that pseudopod activity makes the local cortex temporarily more excitable Ð
thus creating a memory of previous pseudopod locations Ð the model
reproduces experimentally observed zig-zag behavior. Furthermore, the
EC&M model makes four new predictions concerning pseudopod dynamics.
To test these predictions we develop an algorithm that detects pseudopods
via hierarchical clustering of individual membrane extensions. Data from
cell-tracking experiments agrees with all four predictions of the model,
revealing that pseudopod placement is a non-Markovian process affected
by the dynamics of previous pseudopods. The model is also compatible
with known limits of chemotactic sensitivity. In addition to providing a
predictive approach to studying eukaryotic cell motion, the EC&M model
provides a general framework for future models, and suggests directions
for new research regarding the molecular mechanisms underlying directional
persistence.
Submitted by Robert Cooper [rmcooper@princeton.edu]
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[End dictyNews, volume 38, number 9]
