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dictyNews Volume 39 Number 06
dictyNews
Electronic Edition
Volume 39, number 6
March 1, 2013
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.
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Abstracts
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A Dictyostelium secreted factor requires a PTEN-like phosphatase
to slow proliferation and induce chemorepulsion
Sarah E. Herlihy, Yitai Tang, and Richard H. Gomer
PLoS ONE, in press
In Dictyostelium discoideum, AprA and CfaD are secreted proteins
that inhibit cell proliferation. We found that the proliferation of cells
lacking CnrN, a phosphatase and tensin homolog (PTEN)-like
phosphatase, is not inhibited by exogenous AprA and is increased
by exogenous CfaD. The expression of CnrN in cnrNø cells partially
rescues these altered sensitivities, suggesting that CnrN is necessary
for the ability of AprA and CfaD to inhibit proliferation. Cells lacking
CnrN accumulate normal levels of AprA and CfaD. Like cells lacking
AprA and CfaD, cnrNø cells proliferate faster and reach a higher
maximum cell density than wild type cells, tend to be multinucleate,
accumulate normal levels of mass and protein per nucleus, and form
less viable spores. When cnrNø cells expressing myc-tagged CnrN
are stimulated with a mixture of rAprA and rCfaD, levels of
membrane-associated myc-CnrN increase. AprA also causes
chemorepulsion of Dictyostelium cells, and CnrN is required for this
process. Combined, these results suggest that CnrN functions in a
signal transduction pathway downstream of AprA and CfaD
mediating some, but not all, of the effects of AprA and CfaD.
Submitted by Richard Gomer [rgomer@tamu.edu]
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The green tea catechin epigallocatechin gallate (EGCG) blocks cell
motility, chemotaxis and development in Dictyostelium discoideum
Kyle J McQuade, Akihiko Nakajima, April N Ilacqua, Nao Shimada
and Satoshi Sawai
PLOS ONE, in press
Catechins, flavanols found at high levels in green tea, have received
significant attention due to their potential health benefits related to
cancer, autoimmunity and metabolic disease, but little is known about
the mechanisms by which these compounds affect cellular behavior.
Here, we assess whether the model organism Dictyostelium discoideum
is a useful tool with which to characterize the effects of catechins.
Epigallocatechin gallate (EGCG), the most abundant and potent
catechin in green tea, has significant effects on the Dictyostelium life
cycle. In the presence of EGCG aggregation is delayed, cells do not
stream and development is typically stalled at the loose aggregate
stage. The developmental effects very likely result from defects in
motility, as EGCG reduces both random movement and chemotaxis of
Dictyostelium amoebae. These results suggest that catechins and
their derivatives may be useful tools with which to better understand
cell motility and development in Dictyostelium and that this organism
is a useful model to further characterize the activities of catechins.
Submitted by Kyle McQuade [kmcquade@coloradomesa.edu]
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[End dictyNews, volume 39, number 6]
