排序方式: 共有99条查询结果,搜索用时 31 毫秒
1.
Maxim Pilyugin Jeroen Demmers C. Peter Verrijzer Francois Karch Yuri M. Moshkin 《PloS one》2009,4(12)
Histone chaperones are at the hub of a diverse interaction networks integrating a plethora of chromatin modifying activities. Histone H3/H4 chaperone ASF1 is a target for cell-cycle regulated Tousled-like kinases (TLKs) and both proteins cooperate during chromatin replication. However, the precise role of post-translational modification of ASF1 remained unclear. Here, we identify the TLK phosphorylation sites for both Drosophila and human ASF1 proteins. Loss of TLK-mediated phosphorylation triggers hASF1a and dASF1 degradation by proteasome-dependent and independent mechanisms respectively. Consistent with this notion, introduction of phosphorylation-mimicking mutants inhibits hASF1a and dASF1 degradation. Human hASF1b is also targeted for proteasome-dependent degradation, but its stability is not affected by phosphorylation indicating that other mechanisms are likely to be involved in control of hASF1b levels. Together, these results suggest that ASF1 cellular levels are tightly controlled by distinct pathways and provide a molecular mechanism for post-translational regulation of dASF1 and hASF1a by TLK kinases. 相似文献
2.
Ray C. Bartolo Natalie Harfoot Mike Gill Kristy Demmers Bernie McLeod A. Grant Butt 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(8):997-1010
The colon of the brushtail possum does not have an electrogenic secretory response. Given the functional significance of electrogenic
Cl− secretion in the intestine of eutherian mammals, we have investigated the secretory response in the small intestine of this
marsupial. In the Ussing chamber cAMP-dependent secretagogues stimulated a sustained increase in ileal short-circuit current
(Isc), whereas Ca2+-dependent secretagogues induced a transient increase. Both the responses were inhibited by mucosal addition of the anion
channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid (100 μmol l−1), consistent with an anion secretory response. However, the responses were not inhibited by serosal bumetanide (10 μmol l−1) and were independent of bath Cl−, indicating that the stimulated ileal Isc does not involve electrogenic Cl− secretion driven by the NaK2Cl cotransporter, NKCC1. Consistent with this, there were low levels of NKCC1 expression in the
ileal epithelium. In particular, NKCC1 expression in the ileal crypt cells was comparable to that of the villous cells. This
differs from eutherian mammals where high levels of NKCC1 expression in the ileal crypt cells are associated with their role
in Cl− secretion. The cAMP- and Ca2+-dependent secretory responses were inhibited by the removal of HCO3
− suggesting that these responses were due to electrogenic HCO3
− secretion. We conclude that the ileum of the possum does not secrete Cl− due to low levels of NKCC1 expression. It does however appear to secrete HCO3
−. These results are further significant examples of differences in the transport function of the possum intestinal epithelium
compared with eutherian mammals. 相似文献
3.
Maria A. Hegeman Marije P. Hennus Pieter M. Cobelens Annemieke Kavelaars Nicolaas J. G. Jansen Marcus J. Schultz Adrianus J. van Vught Cobi J. Heijnen 《PloS one》2013,8(2)
Background
Ventilator–induced lung injury (VILI) is characterized by vascular leakage and inflammatory responses eventually leading to pulmonary dysfunction. Vascular endothelial growth factor (VEGF) has been proposed to be involved in the pathogenesis of VILI. This study examines the inhibitory effect of dexamethasone on VEGF expression, inflammation and alveolar–capillary barrier dysfunction in an established murine model of VILI.Methods
Healthy male C57Bl/6 mice were anesthetized, tracheotomized and mechanically ventilated for 5 hours with an inspiratory pressure of 10 cmH2O (“lower” tidal volumes of ∼7.5 ml/kg; LVT) or 18 cmH2O (“higher” tidal volumes of ∼15 ml/kg; HVT). Dexamethasone was intravenously administered at the initiation of HVT–ventilation. Non–ventilated mice served as controls. Study endpoints included VEGF and inflammatory mediator expression in lung tissue, neutrophil and protein levels in bronchoalveolar lavage fluid, PaO2 to FiO2 ratios and lung wet to dry ratios.Results
Particularly HVT–ventilation led to alveolar–capillary barrier dysfunction as reflected by reduced PaO2 to FiO2 ratios, elevated alveolar protein levels and increased lung wet to dry ratios. Moreover, VILI was associated with enhanced VEGF production, inflammatory mediator expression and neutrophil infiltration. Dexamethasone treatment inhibited VEGF and pro–inflammatory response in lungs of HVT–ventilated mice, without improving alveolar–capillary permeability, gas exchange and pulmonary edema formation.Conclusions
Dexamethasone treatment completely abolishes ventilator–induced VEGF expression and inflammation. However, dexamethasone does not protect against alveolar–capillary barrier dysfunction in an established murine model of VILI. 相似文献4.
Vanessa Donega Cindy T. J. van Velthoven Cora H. Nijboer Frank van Bel Martien J. H. Kas Annemieke Kavelaars Cobi J. Heijnen 《PloS one》2013,8(1)
Mesenchymal stem cell (MSC) administration via the intranasal route could become an effective therapy to treat neonatal hypoxic-ischemic (HI) brain damage. We analyzed long-term effects of intranasal MSC treatment on lesion size, sensorimotor and cognitive behavior, and determined the therapeutic window and dose response relationships. Furthermore, the appearance of MSCs at the lesion site in relation to the therapeutic window was examined. Nine-day-old mice were subjected to unilateral carotid artery occlusion and hypoxia. MSCs were administered intranasally at 3, 10 or 17 days after hypoxia-ischemia (HI). Motor, cognitive and histological outcome was investigated. PKH-26 labeled cells were used to localize MSCs in the brain. We identified 0.5×106 MSCs as the minimal effective dose with a therapeutic window of at least 10 days but less than 17 days post-HI. A single dose was sufficient for a marked beneficial effect. MSCs reach the lesion site within 24 h when given 3 or 10 days after injury. However, no MSCs were detected in the lesion when administered 17 days following HI. We also show for the first time that intranasal MSC treatment after HI improves cognitive function. Improvement of sensorimotor function and histological outcome was maintained until at least 9 weeks post-HI. The capacity of MSCs to reach the lesion site within 24 h after intranasal administration at 10 days but not at 17 days post-HI indicates a therapeutic window of at least 10 days. Our data strongly indicate that intranasal MSC treatment may become a promising non-invasive therapeutic tool to effectively reduce neonatal encephalopathy. 相似文献
5.
Yuri M. Moshkin Cecile M. Doyen Tsung-Wai Kan Gillian E. Chalkley Karen Sap Karel Bezstarosti Jeroen A. Demmers Zeliha Ozgur Wilfred F. J. van Ijcken C. Peter Verrijzer 《PLoS genetics》2013,9(9)
Chromosome duplication and transmission into daughter cells requires the precisely orchestrated binding and release of cohesin. We found that the Drosophila histone chaperone NAP1 is required for cohesin release and sister chromatid resolution during mitosis. Genome-wide surveys revealed that NAP1 and cohesin co-localize at multiple genomic loci. Proteomic and biochemical analysis established that NAP1 associates with the full cohesin complex, but it also forms a separate complex with the cohesin subunit stromalin (SA). NAP1 binding to cohesin is cell-cycle regulated and increases during G2/M phase. This causes the dissociation of protein phosphatase 2A (PP2A) from cohesin, increased phosphorylation of SA and cohesin removal in early mitosis. PP2A depletion led to a loss of centromeric cohesion. The distinct mitotic phenotypes caused by the loss of either PP2A or NAP1, were both rescued by their concomitant depletion. We conclude that the balanced antagonism between NAP1 and PP2A controls cohesin dissociation during mitosis. 相似文献
6.
Samantha A. Spangler Sabine K. Schmitz Josta T. Kevenaar Esther de Graaff Heidi de Wit Jeroen Demmers Ruud F. Toonen Casper C. Hoogenraad 《The Journal of cell biology》2013,201(6):915-928
The presynaptic active zone mediates synaptic vesicle exocytosis, and modulation of its molecular composition is important for many types of synaptic plasticity. Here, we identify synaptic scaffold protein liprin-α2 as a key organizer in this process. We show that liprin-α2 levels were regulated by synaptic activity and the ubiquitin–proteasome system. Furthermore, liprin-α2 organized presynaptic ultrastructure and controlled synaptic output by regulating synaptic vesicle pool size. The presence of liprin-α2 at presynaptic sites did not depend on other active zone scaffolding proteins but was critical for recruitment of several components of the release machinery, including RIM1 and CASK. Fluorescence recovery after photobleaching showed that depletion of liprin-α2 resulted in reduced turnover of RIM1 and CASK at presynaptic terminals, suggesting that liprin-α2 promotes dynamic scaffolding for molecular complexes that facilitate synaptic vesicle release. Therefore, liprin-α2 plays an important role in maintaining active zone dynamics to modulate synaptic efficacy in response to changes in network activity. 相似文献
7.
Petra Schwertman Karel Bezstarosti Charlie Laffeber Wim Vermeulen Jeroen A.A. Demmers Jurgen A. Marteijn 《Analytical biochemistry》2013,440(2):227-236
Protein ubiquitination plays an important role in the regulation of many cellular processes, including protein degradation, cell cycle regulation, apoptosis, and DNA repair. To study the ubiquitin proteome we have established an immunoaffinity purification method for the proteomic analysis of endogenously ubiquitinated protein complexes. A strong, specific enrichment of ubiquitinated factors was achieved using the FK2 antibody bound to protein G-beaded agarose, which recognizes monoubiquitinated and polyubiquitinated conjugates. Mass spectrometric analysis of two FK2 immunoprecipitations (IPs) resulted in the identification of 296 FK2-specific proteins in both experiments. The isolation of ubiquitinated and ubiquitination-related proteins was confirmed by pathway analyses (using Ingenuity Pathway Analysis and Gene Ontology-annotation enrichment). Additionally, comparing the proteins that specifically came down in the FK2 IP with databases of ubiquitinated proteins showed that a high percentage of proteins in our enriched fraction was indeed ubiquitinated. Finally, assessment of protein–protein interactions revealed that significantly more FK2-specific proteins were residing in protein complexes than in random protein sets. This method, which is capable of isolating both endogenously ubiquitinated proteins and their interacting proteins, can be widely used for unraveling ubiquitin-mediated protein regulation in various cell systems and tissues when comparing different cellular states. 相似文献
8.
9.
Madhuri Salker Gijs Teklenburg Mariam Molokhia Stuart Lavery Geoffrey Trew Tepchongchit Aojanepong Helen J. Mardon Amali U. Lokugamage Raj Rai Christian Landles Bernard A. J. Roelen Siobhan Quenby Ewart W. Kuijk Annemieke Kavelaars Cobi J. Heijnen Lesley Regan Nick S. Macklon Jan J. Brosens 《PloS one》2010,5(4)
Background
Recurrent pregnancy loss (RPL), defined as 3 or more consecutive miscarriages, is widely attributed either to repeated chromosomal instability in the conceptus or to uterine factors that are poorly defined. We tested the hypothesis that abnormal cyclic differentiation of endometrial stromal cells (ESCs) into specialized decidual cells predisposes to RPL, based on the observation that this process may not only be indispensable for placenta formation in pregnancy but also for embryo recognition and selection at time of implantation.Methodology/Principal Findings
Analysis of mid-secretory endometrial biopsies demonstrated that RPL is associated with decreased expression of the decidual marker prolactin (PRL) but increased levels of prokineticin-1 (PROK1), a cytokine that promotes implantation. These in vivo findings were entirely recapitulated when ESCs were purified from patients with and without a history of RPL and decidualized in culture. In addition to attenuated PRL production and prolonged and enhanced PROK1 expression, RPL was further associated with a complete dysregulation of both markers upon treatment of ESC cultures with human chorionic gonadotropin, a glycoprotein hormone abundantly expressed by the implanting embryo. We postulated that impaired embryo recognition and selection would clinically be associated with increased fecundity, defined by short time-to-pregnancy (TTP) intervals. Woman-based analysis of the mean and mode TTP in a cohort of 560 RPL patients showed that 40% can be considered “superfertile”, defined by a mean TTP of 3 months or less.Conclusions
Impaired cyclic decidualization of the endometrium facilitates implantation yet predisposes to subsequent pregnancy failure by disabling natural embryo selection and by disrupting the maternal responses to embryonic signals. These findings suggest a novel pathological pathway that unifies maternal and embryonic causes of RPL. 相似文献10.
Gijs Teklenburg Madhuri Salker Mariam Molokhia Stuart Lavery Geoffrey Trew Tepchongchit Aojanepong Helen J. Mardon Amali U. Lokugamage Raj Rai Christian Landles Bernard A. J. Roelen Siobhan Quenby Ewart W. Kuijk Annemieke Kavelaars Cobi J. Heijnen Lesley Regan Jan J. Brosens Nick S. Macklon 《PloS one》2010,5(4)