dictyNews
Electronic Edition
Volume 44, number 25
September 14, 2018
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Abstracts
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The regulatory subunit phr2AB of Dictyostelium discoideum phosphatase
PP2A interacts with the centrosomal protein CEP161, a CDK5RAP2
ortholog.
Rolf Müller*, Maria Stumpf*, Regina Wehrstedt*, Salil K. Sukumaran,
Malte A. Karow, Marija Marko, Angelika A. Noegel**, Ludwig Eichinger**+
Institute for Biochemistry I, Medical Faculty, University Hospital Cologne,
Joseph-Stelzmann-Str.52, 50931 Cologne, Germany;
Center for Molecular Medicine Cologne (CMMC) and Cologne Cluster on
Cellular Stress Responses in Aging-Associated Diseases (CECAD),
Medical Faculty, University of Cologne, Germany
*equal contributions
**corresponding authors
Genes to Cells, accepted
phr2AB is the regulatory subunit of the Dictyostelium discoideum
phosphatase PP2A and is the ortholog of the human 55B regulatory
subunit of PP2A. phr2AB was isolated as a binding partner of the
centrosomal protein CEP161, an ortholog of mammalian CDK5RAP2.
CEP161 is presumably a phosphoprotein and a component of the Hippo
pathway. The interaction site was located in the N-terminal half of CEP161
which encompasses the gamma-TURC binding domain in CEP161. This
binding domain is responsible for binding of the gamma-tubulin ring
complex which allows microtubule nucleation at the centrosome. GFP-
tagged phr2AB is diffusely distributed throughout the cell and enriched at
the centrosome. Ectopic expression of phr2AB as GFP fusion protein led
to multi-nucleation, aberrant nucleus centrosome ratios and an altered
sensitivity to okadaic acid. Some of these features were also affected in
cells overexpressing domains of CEP161 and in cells from patients
suffering from primary microcephaly, which carried a mutated
CDK5RAP2 gene.
submitted by: Ludwig Eichinger [[log in to unmask]]
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Complex interactions underpin social behaviour in Dictyostelium
giganteum
Santosh Sathe1,2 & Vidyanand Nanjundiah1, 3
1Centre for Ecological Sciences, Indian Institute of Science,
Bangalore 560012, India.
2Department of Plant and Microbial Biology, University of Zürich,
Winterthurerstrasse 190, 8057 Zürich, Switzerland.
3Centre for Human Genetics, Bangalore, 560100, India.
(Email: [log in to unmask])
Behavioral Ecology and Sociobiology, in press
In the wild, social groups of the cellular slime mould amoeba Dictyostelium
giganteum are genetically heterogeneous more often than not¬. When
studied as 1:1 binary mixes, amoebae of one strain almost always form
more spores than the other, an observation that leads one to wonder what
might be responsible for the long-term persistence of different strains in
nature. We have monitored a number of individual and collective traits
bearing on reproductive fitness in chimaeras of Dictyostelium giganteum
obtained by mixing pairs of starved amoebae belonging to distinct wild-type
strains in proportions ranging from 1:9 to 9:1. The main findings are that
intercellular interactions take place at more than one stage of the life cycle,
and that generalisations drawn after mixing cells only in a 1:1 ratio can be
misleading. A strain that does better than another in respect of some
component of fitness (for example, spore formation) may do worse in
respect of a different component (for example, growth rate). Also, a strain
that is a more efficient sporulator than a second strain in one context, may
be less efficient in another context. In addition to such trade-offs, spore
formation in chimaeras can exhibit negative frequency-dependence,
which too can lead to stable coexistence.
submitted by: Santosh Sathe [[log in to unmask]]
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[End dictyNews, volume 44, number 25
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