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CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:A Spatial Stochastic Model of Cell Polarization -
Linda Petzold (University of California)
DTSTART;TZID=Europe/London:20160119T141500
DTEND;TZID=Europe/London:20160119T150000
UID:TALK64651AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/64651
DESCRIPTION:Co-authors: Brian Drawert (UC Santa Barbara)\, Mic
hael Lawson (Uppsala University)\, Tau-Mu Yi (UC S
anta Barbara)\, Mustafa Khammash (ETH Zurich)\, Ot
ger Campas (UC Santa Barbara)\, Michael Trogdon (U
C Santa Barbara) \;AbstractPolarization is an
essential behavior of living cells\, yet the dynam
ics of this symmetry-breaking process are not full
y understood. Previously\, noise was thought to in
terfere with this process\; however\, we show that
stochastic dynamics plan an essential role in rob
ust cell polarization and the dynamic response to
changing cues. \;
To further our unders
tanding of polarization\, we have developed a spat
ial stochastic model of cellular polarization duri
ng mating of Saccharomyces cerevisiae. Specificall
y we investigate the ability of yeast cells to sen
se a spatial gradient of mating pheromone and resp
ond by forming a projection in the direction of th
e mating partner. Our mechanistic model integrates
three components of the polarization process: the
G-protein cycle activated by pheromone bound rece
ptors\, the focusing of a Cdc42 polarization cap\,
and the formation of the tight localization of pr
oteins on the membrane known as the polarisome.&nb
sp\;
Our results demonstrate that higher le
vels of stochastic noise result in increased robus
tness\, giving support to a cellular model where n
oise and spatial heterogeneity combine to achieve
robust biological function. Additionally\, our sim
ulations predict that two positive feedback loops
are required to generate the spatial amplification
to produce focal polarization. We combined our mo
deling with experiments to explore the critical ro
le of the polarisome scaffold protein Spa2 during
yeast mating\, and as a result\, have characterize
d a novel positive feedback loop critical to focal
polarization via the stabilization of actin cable
s. \;
LOCATION:Seminar Room 1\, Newton Institute
CONTACT:INI IT
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