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Your search keyword '"Beullens, Monique"' showing total 6 results
Start Over Author "Beullens, Monique" Journal journal of cell science
6 results on '"Beullens, Monique"'

2. Advanced Microscopy Facility, Vienna Biocenter Core Facilities, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.

Author

Winkler, Claudia, Rouget, Raphael, Wu, Dan, Beullens, Monique, Van Eynde, Aleyde, and Bollen, Mathieu

Subjects
NUCLEAR proteins, PHOSPHOPROTEINS, DEPHOSPHORYLATION, PHOSPHATASES, RNA, DNA, BIOCHEMICAL substrates
Abstract

The ubiquitously expressed nuclear protein NIPP1 (also known as PPP1R8) recruits phosphoproteins for regulated dephosphorylation by the associated protein phosphatase PP1. To bypass the PP1 titration artifacts seen upon NIPP1 overexpression, we have engineered covalently linked fusions of PP1 and NIPP1, and demonstrate their potential to selectively explore the function of the PP1:NIPP1 holoenzyme. By using inducible stable cell lines, we show that PP1--NIPP1 fusions cause replication stress in a manner that requires both PP1 activity and substrate recruitment via the ForkHead Associated domain of NIPP1. More specifically, PP1--NIPP1 expression resulted in the build up of RNA--DNA hybrids (R-loops), enhanced chromatin compaction and a diminished repair of DNA double-strand breaks (DSBs), culminating in the accumulation of DSBs. These effects were associated with a reduced expression of DNA damage signaling and repair proteins. Our data disclose a key role for dephosphorylation of PP1:NIPP1 substrates in setting the threshold for DNA repair, and indicate that activators of this phosphatase hold therapeutic potential as sensitizers for DNA-damaging agents. [ABSTRACT FROM AUTHOR]

Published
2018
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5. Nuclear and subnuclear targeting sequences of the protein phosphatase-1 regulator NIPP1

Author

Jagiello, Izabela, Eynde, Aleyde Van, Vulsteke, Veerle, Beullens, Monique, Boudrez, An, Keppens, Stefaan, Stalmans, Willy, and Bollen, Mathieu

Abstract

NIPP1 is a nuclear subunit of protein phosphatase-1 (PP1) that colocalizes with pre-mRNA splicing factors in speckles. We report here that the nuclear and subnuclear targeting of NIPP1, when expressed in HeLa cells or COS-1 cells as a fusion protein with the enhanced-green-fluorescent protein (EGFP), are mediated by distinct sequences. While NIPP1-EGFP can cross the nuclear membrane passively, the active transport to the nucleus is mediated by two independent nuclear localization signals in the central domain of NIPP1, which partially overlap with binding site(s) for PP1. Furthermore, the concentration of NIPP1-EGFP in the nuclear speckles requires the ‘ForkHead-Associated’ domain in the N terminus. This domain is also required for the nuclear retention of NIPP1 when active transport is blocked. Our data imply that the nuclear and subnuclear targeting of NIPP1 are controlled independently.

Published
2000
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6. Overexpression of PP1-NIPP1 limits the capacity of cells to repair DNA double-strand breaks.

Author

Winkler C, Rouget R, Wu D, Beullens M, Van Eynde A, and Bollen M

Subjects
Chromatin genetics, Chromatin metabolism, Dimerization, Endoribonucleases chemistry, Endoribonucleases metabolism, Gene Expression, HEK293 Cells, Humans, Phosphoprotein Phosphatases chemistry, Phosphoprotein Phosphatases metabolism, Protein Phosphatase 1 chemistry, Protein Phosphatase 1 metabolism, RNA genetics, RNA metabolism, RNA-Binding Proteins chemistry, RNA-Binding Proteins metabolism, DNA Breaks, Double-Stranded, DNA Repair, Endoribonucleases genetics, Phosphoprotein Phosphatases genetics, Protein Phosphatase 1 genetics, RNA-Binding Proteins genetics
Abstract

The ubiquitously expressed nuclear protein NIPP1 (also known as PPP1R8) recruits phosphoproteins for regulated dephosphorylation by the associated protein phosphatase PP1. To bypass the PP1 titration artifacts seen upon NIPP1 overexpression, we have engineered covalently linked fusions of PP1 and NIPP1, and demonstrate their potential to selectively explore the function of the PP1:NIPP1 holoenzyme. By using inducible stable cell lines, we show that PP1-NIPP1 fusions cause replication stress in a manner that requires both PP1 activity and substrate recruitment via the ForkHead Associated domain of NIPP1. More specifically, PP1-NIPP1 expression resulted in the build up of RNA-DNA hybrids (R-loops), enhanced chromatin compaction and a diminished repair of DNA double-strand breaks (DSBs), culminating in the accumulation of DSBs. These effects were associated with a reduced expression of DNA damage signaling and repair proteins. Our data disclose a key role for dephosphorylation of PP1:NIPP1 substrates in setting the threshold for DNA repair, and indicate that activators of this phosphatase hold therapeutic potential as sensitizers for DNA-damaging agents., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2018. Published by The Company of Biologists Ltd.)

Published
2018
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