dictyNews
Electronic Edition
Volume 45, number 4
February 7, 2019
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Abstracts
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Coenzyme A and protein CoAlation levels are regulated in response to
oxidative stress and during morphogenesis in Dictyostelium discoideum
Lujain Aloum,1# Christopher A. Brimson,2# Alexander Zhyvoloup,1
Robert Baines,2 Jovana Bakovic,1 Valeriy Filonenko3,
Christopher R. L. Thompson,2* Ivan Gout1*
1Department of Structural and Molecular Biology, University College
London, London WC1E 6BT, United Kingdom.
2Department of Genetics, Evolution and Environment, University College
London, London WC1E 6BT, United Kingdom.
3Institute of Molecular Biology and Genetics, National Academy of
Sciences of Ukraine, Kyiv 03680, Ukraine.
# These authors contributed equally to this study
*Correspondence should be addressed to I.G.
([log in to unmask]) and C.R.L.T. ([log in to unmask]).
Biochemical and Biophysical Research Communications, in press
Dictyostelium discoideum (D. discoideum) is a simple eukaryote with a
unique life cycle in which it differentiates from unicellular amoebae into
a fruiting body upon starvation. Reactive oxygen species (ROS) have
been associated with bacterial predation, as well as regulatory events
during D. discoideum development and differentiation. Coenzyme A
(CoA) is a key metabolic integrator in all living cells. A novel function of
CoA in redox regulation, mediated by covalent attachment of CoA to
cellular proteins in response to oxidative or metabolic stress, has been
recently discovered and termed protein CoAlation. In this study, we
report that the level of CoA and protein CoAlation in D. discoideum are
developmentally regulated, and correlate with the temporal expression
pattern of genes implicated in CoA biosynthesis during morphogenesis.
Furthermore, treatment of growing D. discoideum cells with oxidising
agents results in a dose-dependent increase of protein CoAlation.
However, much higher concentrations were required when compared to
mammalian cells and bacteria. Increased resistance of D. discoideum to
oxidative stress induced by H2O2 has previously been attributed to high
levels of catalase activity. In support of this notion, we found that H2O2-
induced protein CoAlation is significantly increased in CatA-deficient
D. discoideum cells. Collectively, this study provides insights into the
role of CoA and protein CoAlation in the maintenance of redox
homeostasis in amoeba and during D. discoideum morphogenesis.
submitted by: Chris Thompson [[log in to unmask]]
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Some chemotactic mutants can be progress through development in
chimeric populations
Yuya Kida1, Kai Pan1, Hidekazu Kuwayama*
Faculty of Life and Environmental Sciences, University of Tsukuba,
Tsukuba, Tennodai, 1-1-1, Ibaraki 305-8572, Japan
1 These two authors are equally contributed.
Differentiation, in press
Cell migration in response to morphogen gradients affects morphogenesis.
Chemotaxis towards adenosine 3', 5'-monophosphate (cAMP) is essential
for the early stage of morphogenesis in the slime mold Dictyostelium
discoideum. Here, we show that D. discoideum completes morphogenesis
without cAMP-chemotaxis-dependent cell migration. The extracellular
cAMP gradient is believed to cause cells to form a slug-shaped
multicellular structure and fruiting body. The cAMP receptor, cAR1, was
not expressed at the cell surface during these stages, correlating with
reduced chemotactic activity. Gbeta-null cells expressing temperature
sensitive Gbeta are unable to generate extracellular cAMP (Jin et al.,
1998) and thus unable to aggregate and exhibit proper morphogenesis
under restrictive temperature. However, when mixed with wild type cells
ts-Gbeta expressing gbeta-null cells normally aggregated and exhibited
normal morphogenesis under restrictive temperature. Furthermore, cells
migrated after aggregation in a mixture containing wild-type cells. KI-5
cells, which do not show aggregation or morphogenesis, spontaneously
migrated to a transplanted wild-type tip and underwent normal
morphogenesis and cell differentiation; this was not observed in cells
lacking tgrB1and tgrC1 cells adhesion molecules. Thus, cAMP gradient-
dependent cell migration may not be required for multicellular pattern
formation in late Dictyostelium development.
submitted by: Hidekazu Kuwayama [[log in to unmask]]
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Dicty in the news from the LMB website:
https://www2.mrc-lmb.cam.ac.uk/a-master-regulator-of-cell-movement-in-response-to-chemical-signals/
submitted by: Rob Kay [[log in to unmask]]
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