排序方式: 共有23条查询结果,搜索用时 62 毫秒
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Yang XX Hawle P Bebelman JP Meenhuis A Siderius M van der Vies SM 《FEMS yeast research》2007,7(6):796-807
Cdc37p, the p50 homolog of Saccharomyces cerevisiae, is an Hsp90 cochaperone involved in the targeting of protein kinases to Hsp90. Here we report a role for Cdc37p in osmoadaptive signalling in this yeast. The osmosensitive phenotype that is displayed by the cdc37-34 mutant strain appears not to be the consequence of deficient signalling through the high osmolarity glycerol (HOG) MAP kinase pathway. Rather, Cdc37p appears to play a role in the filamentous growth (FG) pathway, which mediates adaptation to high osmolarity parallel to the HOG pathway. The osmosensitive phenotype of the cdc37-34 mutant strain is aggravated upon the deletion of the HOG gene. We report that the hyper-osmosensitive phenotype of the cdc37-34, hog1 mutant correlates to a reduced of activity of the FG pathway. We utilized this phenotype to isolate suppressor genes such as KSS1 that encodes a MAP kinase that functions in the FG pathway. We report that Kss1p interacts physically with Cdc37p. Like Kss1p, the second suppressor that we isolated, Dse1p, is involved in cell wall biogenesis or maintenance, suggesting that Cdc37p controls osmoadapation by regulating mitogen-activated protein kinase signalling aimed at adaptive changes in cell wall organization. 相似文献
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Jan-Paul Flacke Sanjeev Kumar Sawa Kostin H. Peter Reusch Yury Ladilov 《Apoptosis : an international journal on programmed cell death》2009,14(1):90-96
To analyze the underlying cellular mechanisms of adaptation to ischemia-induced apoptosis through short acidic pretreatment,
i.e. acidic preconditioning (APC), Wistar rat coronary endothelial cells (EC) were exposed for 40 min to acidosis (pH 6.4)
followed by a 14 h recovery period (pH 7.4) and finally treated for 2 h with simulated in vitro ischemia (glucose-free anoxia
at pH 6.4). APC led to a transient activation of p38 and Akt kinases, but not of JNK and ERK1/2 kinases, which was accompanied
by significant reduction of the apoptotic cell number, caspase-12/-3 cleavage and Bcl-xL overexpression. These effects of
APC were completely abolished by prevention of Akt- or p38-phosphorylation during APC. Furthermore, knock-down of Bcl-xL by
siRNA-transfection also abolished the anti-apoptotic effect of APC. Therefore, APC leads to protection of EC against ischemic
apoptosis by activation of Akt and p38 followed by overexpression of Bcl-xL, which is a key anti-apoptotic mechanism of APC. 相似文献
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A Saccharomyces cerevisiae strain in which the GPP1 and GPP2 genes, both encoding glycerol-3-phosphate phosphatase isoforms, are deleted, displays both osmo- and thermosensitive (ts)
phenotypes. We isolated genes involved in cell wall maintenance as multicopy suppressors of the gpp1gpp2 ts phenotype. We found that the gpp1gpp2 strain is hypersensitive to cell wall stress such as treatment with β-1,3-glucanase containing cocktail Zymolyase and chitin-binding
dye Calcofluor-white (CFW). Sensitivity to Zymolyase was rescued by overexpression of SSD1, while CFW sensitivity was rescued by SSD1, FLO8 and WSC3—genes isolated as multicopy suppressors of the gpp1gpp2 ts phenotype. Some of the isolated suppressor genes (SSD1, FLO8) also rescued the lytic phenotype of slt2 deletion strain. Additionally, the sensitivity to CFW was reduced when the cells were supplied with glycerol. Both growth on glycerol-based
medium and overexpression of SSD1, FLO8 or WSC3 had additive suppressing effect on CFW sensitivity of the gpp1gpp2 mutant strain. We also confirmed that the internal glycerol level changed in cells exposed to cell wall perturbation. 相似文献
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Bauke Zelle Marie Pauline J. Evers Peter C. Groot Jan Paul Bebelman Willem H. Mager Rudi J. Planta Jan C. Pronk Stephan G. M. Meuwissen Martin H. Hofker Aldur W. Eriksson Rune R. Frants 《Human genetics》1988,78(1):79-82
Summary A human cosmid library was screened with a pepsinogen A (PGA) cDNA probe, yielding 18 clones with (parts of) one, two or three PGA genes. By aligning these cosmids a restriction map of a PGA gene quadruplet was obtained in which the four genes are arranged in a highly ordered fashion in a head-to-tail orientation. Using the length in kilobases of the large polymorphic EcoRI fragment of the PGA genes, this quadruplet can be described as 15.0-12.0-12.0-16.6. An AvaII polymorphism allowed us to identify the two PGA haplotypes of the individual whose DNA had been cloned in the cosmid library to be a gene triplet and a gene quadruplet. By comparing the restriction maps of the central 12.0 genes in these multiplets to those of the flanking 15.0 and 16.6 genes, we postulate that these central genes arose from unequal but homologous crossing over between two 15.0–16.6 gene pairs. This hypothesis provides for the creation of a variety of haplotypes by additional cross overs and mutations. Southern blots of family and population material supports the existance of at least five common PGA haplotypes, including a single-gene haplotype, giving rise to a large number of different EcoRI patterns. The single PGA gene is probably the reciprocal crossing over product. Comparison between the DNA and protein polymorphisms suggests further micro-heterogeneity in the different PGA haplotypes. 相似文献
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Sanjeev Kumar Sawa Kostin Jan-Paul Flacke H. Peter Reusch Yury Ladilov 《The Journal of biological chemistry》2009,284(22):14760-14768
The cAMP signaling pathway plays an essential role in modulating the
apoptotic response to various stress stimuli. Until now, it was attributed
exclusively to the activity of the G-protein-responsive transmembrane adenylyl
cyclase. In addition to transmembrane AC, mammalian cells possess a second
source of cAMP, the ubiquitously expressed soluble adenylyl cyclase (sAC).
However, the role of this cyclase in apoptosis was unknown. A mitochondrial
localization of this cyclase has recently been demonstrated, which led us to
the hypothesis that sAC may play a role in apoptosis through modulation of
mitochondria-dependent apoptosis. To prove this hypothesis, apoptosis was
induced by simulated in vitro ischemia or by acidosis, which is an
important component of ischemia. Suppression of sAC activity with the
selective inhibitor KH7 or sAC knockdown by small interfering RNA transfection
abolished endothelial apoptosis. Furthermore, pharmacological inhibition or
knockdown of protein kinase A, an important cAMP target, demonstrated a
significant anti-apoptotic effect. Analysis of the underlying mechanisms
revealed (i) the translocation of sAC to mitochondria under acidic stress and
(ii) activation of the mitochondrial pathway of apoptosis, i.e.
cytochrome c release and caspase-9 cleavage. sAC inhibition or
knockdown abolished the activation of the mitochondrial pathway of apoptosis.
Analysis of mitochondrial co-localization of Bcl-2 family proteins
demonstrated sAC- and protein kinase A-dependent translocation of Bax to
mitochondria. Taken together, these results suggest the important role of sAC
in modulating the mitochondria-dependent pathway of apoptosis in endothelial
cells.Increasing evidence suggests that apoptosis of endothelial cells
(EC)3 may be
responsible for acute and chronic vascular diseases, e.g. through
atherogenesis (1), endothelial
dysfunction (2), or thrombosis
(3). Within several signaling
mechanisms, a cAMP-dependent signaling pathway plays a substantial role in
mediating apoptotic cell death induced by various stress factors. Elevation of
the cellular cAMP either by forskolin-induced stimulation of the
G-protein-responsive transmembrane adenylyl cyclase (tmAC) or by treatment
with cAMP analogs has been shown to lead to both induction and suppression of
apoptosis in different cell types
(4–7).
This discrepancy may be due to differences in cell types and experimental
models. Alternatively, a lack of specificity of tmAC-induced signals,
especially directed to distant intracellular targets like mitochondria, may be
a cause of the discrepancy. Indeed, the classical model of cAMP signaling
requires the diffusion of cAMP from plasma membrane-localized tmAC to targets
localized throughout the cell. Diffusion of cAMP throughout the cytosol makes
it difficult to selectively activate distally localized targets without also
activating more proximal targets. Therefore, such diffusion of cAMP would
likely diminish specificity, selectivity, and signal strength. This model is
further complicated by the presence of phosphodiesterases, which degrade cAMP,
thus preventing its diffusion.In addition to tmAC, a second source of cAMP, soluble adenylyl cyclase
(sAC), was demonstrated for mammalian cells
(8,
9). Cytosolic localization of
sAC provides both specificity and selectivity by permitting generation of cAMP
proximal to intracellular targets. Furthermore, this model for cAMP action
incorporates phosphodiesterases, which would act to limit diffusion and
prevent nonspecific effector activation.Whether sAC participates in apoptosis was unknown. A previous report
demonstrated that sAC is co-localized with mitochondria
(10). Because mitochondria
play a fundamental role in apoptosis
(11), we hypothesized that sAC
may influence the development of apoptosis by modulating the mitochondrial
pathway of apoptosis. Therefore, we aimed to examine the role of sAC in
apoptotic cell death, especially its role in the modulation of the
mitochondria-dependent pathway of apoptosis. For this purpose, apoptosis was
induced in rat coronary EC by simulated in vitro ischemia or by
acidosis. By applying pharmacological inhibition of sAC or small interfering
RNA (siRNA)-mediated sAC knockdown, we found that sAC activity is required for
the induction of apoptosis by ischemia or acidosis. Additionally,
translocation of sAC to mitochondria and the sAC-dependent release of
cytochrome c suggest that this cyclase specifically regulates the
mitochondrial pathway of apoptosis. 相似文献
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ten Hallers EJ Marres HA Rakhorst G Jansen JA Sommers MG Van der Houwen EB Schutte HK Van Kooten TG Van Loon JP Verkerke GJ 《Laboratory animals》2007,41(2):270-284
A modern way of voice rehabilitation after total laryngectomy includes the use of shunt valves and tracheostoma valves. Problems of fixation to the surrounding tissue are a major drawback in the use of the shunt valve, heat and moisture exchange (HME) filters and, especially, the tracheostoma valve. To solve these problems different tissue connectors were developed. The main objective was to test the feasibility of these prototypes in a new animal model. Here we discuss the results, problems and complications of the selected Saanen goat model. In this prospective laboratory study, 19 healthy adult female Saanen goats (Capra hircus) were used and observed post-surgically for 12 weeks. Selection criteria such as comparable anatomy to humans and easy handling were used for animal model development. Also a literature search using the Medline and the ISI Web of Science databases was performed. The anatomy of the Saanen goat was investigated in a separate postmortem study. Surgery consisted of a laryngotracheal separation and implantation of a tracheo-oesophageal and tracheostoma tissue connector with fibrin tissue glue. Postoperative care consisted of frequent stoma care, monitoring appetite, weight, vital signs and administration of antibiotics, analgesics and mucolytic agents. All animals survived the surgical procedure. However, postoperative care was extensive, labour intensive and was accompanied by several complications. Eleven animals died spontaneously before the end of the experiment. The tracheostoma tissue connector caused signs of local infection in all cases. There was no evidence of infection around the tracheo-oesophageal tissue connector in 18 cases. It was concluded that the use of goats in this tracheostoma model was associated with major complications and should, therefore, only be used for short-term experiments with intensive care. Additional research is needed to see if clinical application of the tissue connectors is possible in the future. 相似文献
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Vincenzo Torraca Chao Cui Ralf Boland Jan-Paul Bebelman Astrid M. van der Sar Martine J. Smit Marco Siderius Herman P. Spaink Annemarie H. Meijer 《Disease models & mechanisms》2015,8(3):253-269
The recruitment of leukocytes to infectious foci depends strongly on the local release of chemoattractant mediators. The human CXC chemokine receptor 3 (CXCR3) is an important node in the chemokine signaling network and is expressed by multiple leukocyte lineages, including T cells and macrophages. The ligands of this receptor originate from an ancestral CXCL11 gene in early vertebrates. Here, we used the optically accessible zebrafish embryo model to explore the function of the CXCR3-CXCL11 axis in macrophage recruitment and show that disruption of this axis increases the resistance to mycobacterial infection. In a mutant of the zebrafish ortholog of CXCR3 (cxcr3.2), macrophage chemotaxis to bacterial infections was attenuated, although migration to infection-independent stimuli was unaffected. Additionally, attenuation of macrophage recruitment to infection could be mimicked by treatment with NBI74330, a high-affinity antagonist of CXCR3. We identified two infection-inducible CXCL11-like chemokines as the functional ligands of Cxcr3.2, showing that the recombinant proteins exerted a Cxcr3.2-dependent chemoattraction when locally administrated in vivo. During infection of zebrafish embryos with Mycobacterium marinum, a well-established model for tuberculosis, we found that Cxcr3.2 deficiency limited the macrophage-mediated dissemination of mycobacteria. Furthermore, the loss of Cxcr3.2 function attenuated the formation of granulomatous lesions, the typical histopathological features of tuberculosis, and led to a reduction in the total bacterial burden. Prevention of mycobacterial dissemination by targeting the CXCR3 pathway, therefore, might represent a host-directed therapeutic strategy for treatment of tuberculosis. The demonstration of a conserved CXCR3-CXCL11 signaling axis in zebrafish extends the translational applicability of this model for studying diseases involving the innate immune system.KEY WORDS: Macrophage biology, Tuberculosis, Chemokine, CXCR3, CXCL11, Mycobacterium, Zebrafish, Immunology 相似文献