A5019399074- Epigenetics and DNA Methylation
- RNA Research and Splicing
- Protein Tyrosine Phosphatases
- RNA modifications and cancer
- Microtubule and mitosis dynamics
- Cancer-related gene regulation
- ATP Synthase and ATPases Research
- Protein Kinase Regulation and GTPase Signaling
- Ubiquitin and proteasome pathways
- Prostate Cancer Treatment and Research
- Nuclear Structure and Function
- Cancer-related Molecular Pathways
- DNA Repair Mechanisms
- Enzyme Structure and Function
- RNA and protein synthesis mechanisms
- FOXO transcription factor regulation
- Genomics and Chromatin Dynamics
- Prostate Cancer Diagnosis and Treatment
- CRISPR and Genetic Engineering
- Endoplasmic Reticulum Stress and Disease
- Liver Disease Diagnosis and Treatment
- Fungal and yeast genetics research
- Telomeres, Telomerase, and Senescence
- Enzyme Production and Characterization
- Reproductive Biology and Fertility
KU Leuven
2012-2024
VIB-KU Leuven Center for Cancer Biology
2016
Brown University
2012
Miyagi Prefectural Hospital Organization
2010
University of Oslo
2006
Vlaams Instituut voor Biotechnologie
2005
The ubiquitous protein Ser/Thr phosphatase-1 (PP1) interacts with dozens of regulatory proteins that are structurally unrelated. However, most them share a short, degenerate "RVxF"-type docking motif. Using broad in silico screening based on stringent definition the RVxF motif, combination multistep biochemical validation procedure, we have identified 78 novel mammalian PP1 interactors. A global analysis validated RVxF-based interactome not only provided insights into conserved features...
Abstract Critical cancer pathways often cannot be targeted because of limited efficiency crossing cell membranes. Here we report the development a Salmonella-based intracellular delivery system to address this challenge. We engineer genetic circuits that (1) activate regulator flhDC drive invasion and (2) induce lysis release proteins into tumor cells. Released protein drugs diffuse from Salmonella containing vacuoles cellular cytoplasm where they interact with their therapeutic targets....
Autotaxin (NPP2) is an extracellular protein that upregulated in various malignancies, including breast and lung cancer. It potently stimulates cell proliferation, motility angiogenesis, which accounted for by its intrinsic lysophospholipase-D activity generates the lipid mediators lysophosphatidic acid sphingosine-1-phosphate. Based on structural similarities with better characterized nucleotide pyrophosphatase/phosphodiesterase NPP1, it has always been assumed NPP2 also synthesized as a...
Nuclei from bovine thymus contain a high level of partially latent protein phosphatase 1 (PP-1). More than 90% this PP-1 is associated with the insoluble chromatin/matrix fraction and can be extracted 0.3 M NaCl. The salt extract also contains three heat- acid-stable inhibitory proteins that resolved on Mono Q. We have purified two these nuclear inhibitors (NIPP-1a NIPP-1b) until homogeneity. They are acidic (pI = 4.4) molecular mass 18 kDa (NIPP-1a) 16 (NIPP-1b) SDS-PAGE. Judged larger was...
Maternal embryonic leucine zipper kinase (MELK), a serine/threonine protein kinase, has oncogenic properties and is overexpressed in many cancer cells. The function of MELK attributed to its capacity disable critical cell-cycle checkpoints reduce replication stress. Most functional studies have relied on the use siRNA/shRNA-mediated gene silencing. In present study, we explored biological using MELK-T1, novel selective small-molecule inhibitor. Strikingly, MELK-T1 triggered rapid...
NIPP-1 was originally isolated as a potent and specific nuclear inhibitory polypeptide (16-18 kDa) of protein phosphatase-1. We report here the cDNA cloning from bovine thymus show that native consists 351 residues has calculated mass 38.5 kDa. The bacterially expressed central third completely inhibited type-1 catalytic subunit, but displayed reduced potency after phosphorylation by kinase A casein 2. Translation mRNA in reticulocyte lysates resulted accumulation both intact smaller...
NIPP1 is a regulatory subunit of species protein phosphatase-1 (PP1) that co-localizes with splicing factors in nuclear speckles. We report the N-terminal third largely consists Forkhead-associated (FHA) interaction domain, known phosphopeptide module. A yeast two-hybrid screening revealed an between this domain and human homolog (CDC5L) fission cdc5, which required for G<sub>2</sub>/M progression pre-mRNA splicing. CDC5L co-localized speckles COS-1 cells. Furthermore, CDC5L, NIPP1, PP1 rat...
NIPP1 is a ubiquitous nuclear protein that required for spliceosome assembly. We report here the phosphothreonine-binding Forkhead-associated domain of interacts with cell cycle-regulated Ser/Thr kinase MELK (maternal embryonic leucine zipper kinase). The NIPP1-MELK interaction was critically dependent on phosphorylaton Thr-478 and increased in lysates from mitotically arrested cells. Recombinant potent inhibitor an early step assembly extracts. This splicing defect also seen kinase-dead...
NIPP-1 is a subunit of the major nuclear protein phosphatase-1 (PP-1) in mammalian cells and potently inhibits PP-1 activity vitro. Using yeast two-hybrid co-sedimentation assays, we mapped PP-1-binding site inhibition function to central one-third domain NIPP-1. Full-length (351 residues) domain, NIPP-1143–217, were equally potent inhibitors (IC50 = 0.3 nm). Synthetic peptides spanning further narrowed inhibitory residues 191–200. A second, noninhibitory was identified by far-Western assays...
We have recently purified two potent and specific inhibitory polypeptides of protein phosphatase-1 from the particulate fraction bovine thymus nuclei (Beullens, M., Van Eynde, A., Stalmans, W., Bollen, M. (1992) J. Biol. Chem. 267, 16538-16544). Here it is reported that these inhibitors, termed NIPP-1a (18 kDa) NIPP-1b (16 kDa), are excellent substrates (Km = 0.1 microM) for phosphorylation by kinase A on both Ser Thr residues. Phosphorylation was temporally closely related with an...
Protein Ser/Thr phosphatase-1 (PP1) is a ubiquitous eukaryotic enzyme that controls numerous cellular processes by the dephosphorylation of key regulatory proteins. PP1 expressed in various compartments but most abundant nucleus. We have examined determinants for nuclear localization enhanced green fluorescent protein-tagged COS1 cells. Our studies show PP1gamma(1) does not contain functional signal and its accumulation require Sds22, which has previously been implicated yeast (Peggie, M....
CDK9/cyclin T1, a key enzyme in HIV-1 transcription, is negatively regulated by 7SK RNA and the HEXIM1 protein. Dephosphorylation of CDK9 on Thr(186) protein phosphatase 1 (PP1) stress-induced cells or M1A normally growing activates CDK9. Our previous studies showed that Tat binds to PP1 through Q(35)VCF(38) sequence, which similar PP1-binding RVXF motif this interaction facilitates transcription. In present study, we analyzed effect expression central domain nuclear inhibitor (cdNIPP1) an...
The histone methyltransferase EZH2 regulates cell proliferation and differentiation by silencing Polycomb group target genes. NIPP1, a nuclear regulator of serine/threonine protein phosphatase 1 (PP1), has been implicated in the regulation occupancy at loci, but underlying mechanism is not understood. Here, we demonstrate that phosphorylation cyclin-dependent kinases Thr416 creates docking site for ForkHead-associated domain NIPP1. Recruited NIPP1 enables net inhibiting its dephosphorylation...
Maternal embryonic leucine zipper kinase (MELK) belongs to the subfamily of AMP-activated Ser/Thr protein kinases. The expression MELK is very high in glioblastoma-type brain tumors, but it not clear how this contributes tumor growth. Here we show that siRNA-mediated loss U87 MG glioblastoma cells causes a G1/S phase cell cycle arrest accompanied by death or senescence-like phenotype can be rescued siRNA-resistant MELK. This mediated an increased p21(WAF1/CIP1), inhibitor cyclin-dependent...
Prostate cancer (PCa) is a very heterogeneous disease with respect to clinical outcome. This study explored differential DNA methylation in priori selected genes diagnose PCa and predict failure (CF) high-risk patients.A quantitative multiplex, methylation-specific PCR assay was developed assess promoter of the APC, CCND2, GSTP1, PTGS2 RARB formalin-fixed, paraffin-embedded tissue samples from 42 patients benign prostatic hyperplasia radical prostatectomy specimens PCa, encompassing training...
ABSTRACT The serine/threonine protein phosphatase-1 (PP1) complex is a key regulator of the cell cycle. However, redundancy PP1 isoforms and lack specific inhibitors have hampered studies on global role in cycle progression vertebrates. Here, we show that overexpression nuclear inhibitor (NIPP1; also known as PPP1R8) HeLa cells culminated prometaphase arrest, associated with severe spindle-formation chromosome-congression defects. In addition, spindle assembly checkpoint was activated...
SDS22 forms an inactive complex with nascent protein phosphatase PP1 and Inhibitor-3. SDS22:PP1:Inhibitor-3 is a substrate for the ATPase p97/VCP, which liberates binding to canonical regulatory subunits. The exact role of in PP1-holoenzyme assembly remains elusive. Here, we show that stabilizes PP1. In absence SDS22, gradually lost, resulting hyperphosphorylation proliferation arrest. Similarly, identify female individual severe neurodevelopmental disorder bearing unstable mutant,...