ABSTRACTS – ORAL PRESENTATIONS - AMCA, spol. s r.o.

phosphatase (also called PPM1D) dephosphorylates multiple proteins involved in DDR
and is essential for timely termination of the DDR (Medema and Macurek, 2012). Here
we have investigated how Wip1 is regulated in the context of the cell cycle (Macurek
et al., 2013). Wip1 protein level increases from G1 phase to G2 and declines in mitosis.
Decreased level of Wip1 during mitosis is caused by proteasomal degradation in APC/
C-cdc20-dependent manner. In addition, Wip1 is phosphorylated at multiple residues
during mitosis and this leads to inhibition of its enzymatic activity. Importantly, ectopic
expression of Wip1 reduced γH2AX foci number in mitotic cells and decreased the
number of 53BP1 nuclear bodies in G1 cells. We propose that the combined degradation
and inhibition of Wip1 in mitosis decreases the threshold necessary for DDR activation
and enables cells to react even to modest levels of DNA damage encountered during
unperturbed mitotic progression.
Acknowledgements:
We are thankful to Dr. Staněk (IMG, Prague) for making the Scan^R imaging station
available and all members of our laboratories for helpful discussions. This work was
supported by the Grant Agency of the Czech Republic (projects P305/10/P420 and
P301/10/1525), the Netherlands Genomic Initiative of NWO (CGC), the Danish Cancer
Society and the European Commission (project DDResponse). AL was supported by
Swedish Cancer Foundation and Swedish Childhood Cancer Foundation.
References:
Bartek, J. & Lukas, J. (2007), ‚DNA damage checkpoints: from initiation to recovery or
adaptation.‘, Curr. Opin. Cell Biol. 19(2), 238-245.
Lukas, J.; Lukas, C. & Bartek, J. (2011), ‚More than just a focus: The chromatin response
to DNA damage and its role in genome integrity maintenance.‘, Nat Cell Biol 13(10),
1161-1169.
Macurek L, Benada J, Müllers E, Halim VA, Krejčíková K, Burdová K, Soňa Pecháčková,
Zdeněk Hodný, Arne Lindqvist, René H Medema and Jiri Bartek (2013), ‚Downregulation
of Wip1 phosphatase modulates the cellular threshold of DNA damage signaling in
mitosis.‘ Cell Cycle; 12(2): 251–262.
Medema, R. H. and Macurek, L. (2012), ‚Checkpoint control and cancer.’ Oncogene
31(21), 2601-2613.
71. ANALYSIS OF MAST CELL MOTILITY, MORPHOLOGY AND ACTIVATION USING
QUANTITATIVE IMAGE-BASED CYTOMETRY
Monika Bambousková, Ivana Hálová, Petr Dráber
Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague,
Czech Republic; monika.bambouskova@img.cas.cz
Mast cells are important component of innate and adaptive host immune system. They
contribute to protection against helminths and bacterial infection and play a role in
angiogenesis and autoimmunity. Under pathological conditions mast cells are involved in
allergic and inflammatory diseases (1). Enhanced accumulation of mast cells in inflamed
Analytical Cytometry VII 85