共查询到20条相似文献,搜索用时 9 毫秒
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钙调素高表达对NRK细胞中DG-PKC和cAMP-PKA水平的影响 总被引:1,自引:0,他引:1
钙调素(CaM)作为Ca2+的主要受体,对细胞增殖起重要调节作用,而且在转化细胞中CaM的水平明显高于正常细胞.cAMP作为一种第二信使,起着将细胞外刺激信号转化为细胞内各种生理活动的媒介作用.蛋白激酶A(PKA)则是这种转化过程中的关键激酶.蛋白激... 相似文献
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Anna Zorina Natalia Stepanchenko Galina V. Novikova Maria Sinetova Vladimir B. Panichkin Igor E. Moshkov Vladislav V. Zinchenko Sergey V. Shestakov Iwane Suzuki Norio Murata Dmitry A. Los 《DNA research》2011,18(3):137-151
Serine/threonine protein kinases (STPKs) are the major participants in intracellular signal transduction in eukaryotes, such as yeasts, fungi, plants, and animals. Genome sequences indicate that these kinases are also present in prokaryotes, such as cyanobacteria. However, their roles in signal transduction in prokaryotes remain poorly understood. We have attempted to identify the roles of STPKs in response to heat stress in the prokaryotic cyanobacterium Synechocystis sp. PCC 6803, which has 12 genes for STPKs. Each gene was individually inactivated to generate a gene-knockout library of STPKs. We applied in vitro Ser/Thr protein phosphorylation and phosphoproteomics and identified the methionyl-tRNA synthetase, large subunit of RuBisCO, 6-phosphogluconate dehydrogenase, translation elongation factor Tu, heat-shock protein GrpE, and small chaperonin GroES as the putative targets for Ser/Thr phosphorylation. The expressed and purified GroES was used as an external substrate to screen the protein extracts of the individual mutants for their Ser/Thr kinase activities. The mutants that lack one of the three protein kinases, SpkC, SpkF, and SpkK, were unable to phosphorylate GroES in vitro, suggesting possible interactions between them towards their substrate. Complementation of the mutated SpkC, SpkF, and SpkK leads to the restoration of the ability of cells to phosphorylate the GroES. This suggests that these three STPKs are organized in a sequential order or a cascade and they work one after another to finally phosphorylate the GroES. 相似文献
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《Molecular cell biology research communications》1999,1(3):221-226
It has been well established that increases in extracellular calcium concentration ([Ca2+]) inhibit parathyroid hormone (PTH) secretion. The effects of [Ca2+] are mediated through a G-protein-coupled receptor that has been cloned and characterized. Additionally, it has been demonstrated in parathyroid cells that an increase in [Ca2+] results in an increase in steady-state levels of intracellular calcium ([Ca2+]i). At present, it has not been fully resolved whether changes in [Ca2+]i are related to changes in PTH secretion. In the current study, the effect of increased [Ca2+] on PTH secretion and the connection regarding changes in concentrations of intracellular calcium [Ca2+]i have been examined in primary cultures of bovine parathyroid cells. PTH secretion was measured by radioimmunoassay and intracellular calcium was determined by single cell calcium imaging. Bovine parathyroid cells pre-incubated with either 0.5 or 1 mM calcium responded to rapid increases in [Ca2+] (≥0.5 mM) with an immediate and sustained increase in steady-state levels of [Ca2+]i that persisted for time intervals greater than 15 minutes. Although the magnitude of the sustained increase in [Ca2+]i varied among individual cells (∼40% to >300%), the overall pattern and course of time were similar in all cells examined (n = 142). In all trials, [Ca2+]i immediately returned to baseline levels following the addition of the calcium chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA). Additional control studies, however, suggest that sustained increases in [Ca2+]i do not correlate with regulation of parathyroid hormone secretion. Sustained elevations of [Ca2+]i were not observed when [Ca2+] was gradually increased by the addition of 0.1 mM increments at 1 minute intervals. Furthermore, the effect on inhibition of PTH secretion was the same regardless of whether [Ca2+] was increased by gradual or rapid addition. 相似文献
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Xin Wu Tongda Xu Dongye Li Shasha Zhu Qiuping Chen Wenjing Hu Defeng Pan Hong Zhu Hong Sun 《PloS one》2013,8(12)
Luteolin has long been used in traditional Chinese medicine for treatment of various diseases. Recent studies have suggested that administration of luteolin yields cardioprotective effects during ischemia/reperfusion (I/R) in rats. However, the precise mechanisms of this action remain unclear. The aim of this study is to confirm that luteolin-mediated extracellular signal regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) pathways are responsible for their cardioprotective effects during I/R. Wistar rats were divided into the following groups: (i) DMSO group (DMSO); (ii) I/R group (I/R); (iii) luteolin+I/R group (Lut+I/R); (iv) ERK1/2 inhibitor PD98059+I/R group (PD+I/R); (v) PD98059+luteolin+I/R group (PD+Lut+I/R); and (vi) JNK inhibitor SP600125+I/R group (SP+I/R). The following properties were measured: contractile function of isolated heart and cardiomyocytes; infarct size; the release of lactate dehydrogenase (LDH); the percentage of apoptotic cells; the expression levels of Bcl-2 and Bax; and phosphorylation status of ERK1/2, JNK, type 1 protein phosphatase (PP1a), phospholamban (PLB) and sarcoplasmic reticulum Ca2+-ATPase (SERCA2a). Our data showed that pretreatment with luteolin or SP600125 significantly improved the contraction of the isolated heart and cardiomyocytes, reduced infarct size and LDH activity, decreased the rate of apoptosis and increased the Bcl-2/Bax ratio. However, pretreatment with PD98059 alone before I/R had no effect on the above indexes. Further, these consequences of luteolin pretreatment were abrogated by co-administration of PD98059. We also found that pretreatment with PD98059 caused a significant increase in JNK expression, and SP600125 could cause ERK1/2 activation during I/R. In addition, we are the first to demonstrate that luteolin affects PP1a expression, which results in the up-regulation of the PLB, thereby relieving its inhibition of SERCA2a. These results showed that luteolin improves cardiomyocyte contractile function after I/R injury by an ERK1/2-PP1a-PLB-SERCA2a-mediated mechanism independent of JNK signaling pathway. 相似文献
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Adenosine 3′,5′-cyclic monophosphate (cAMP) is known to stimulate exogenous IsK channel current in the Xenopus oocyte expression system. The present study was performed to determine whether elevation of cytosolic cAMP in a native mammalian
epithelium known to secrete K+ through endogenously expressed IsK channels would stimulate K+ secretion through these channels. The equivalent short circuit current (I
sc
) across vestibular dark cell epithelium in gerbil was measured in a micro-Ussing chamber and the apical membrane current
(I
IsK
) and conductance (g
IsK
) of IsK channels was recorded with both the on-cell macro-patch and nystatin-perforated whole-cell patch-clamp techniques. It has
previously been shown that I
sc
can be accounted for by transepithelial K+ secretion and that the apical IsK channels constitute a significant pathway for K+ secretion. The identification of the voltage-dependent whole-cell currents in vestibular dark cells was strengthened by the
finding that a potent blocker of IsK channels, chromanol 293B, strongly reduced I
IsK
from 646 ± 200 to 154 ± 22 pA (71%) and g
IsK
from 7.5 ± 2.6 to 2.8 ± 0.4 nS (53%). Cytoplasmic cAMP was elevated by applying dibutyryl cyclic AMP (dbcAMP), or the phosphodiesterase
inhibitors 3-isobutyl-1-methylxanthine (IBMX) and Ro-20-1724. dbcAMP (1 mm) increased I
sc
and I
IsK
from 410 ± 38 to 534 ± 40 μA/cm2 and from 4.3 ± 0.8 to 11.4 ± 2.2 pA, respectively. IBMX (1 mm) caused transient increases of I
sc
from 415 ± 30 to 469 ± 38 μA/cm2 and Ro-20-1724 (0.1 mm) from 565 ± 43 to 773 ± 58 μA/cm2. IBMX increased I
IsK
from 5.5 ± 1.5 to 16.9 ± 5.8 pA in on-cell experiments and from 191 ± 31 to 426 ± 53 pA in whole-cell experiments. The leak
conductance due to all non-IsK channel sources did not change during dbcAMP and IBMX while 293B in the presence of dbcAMP reduced I
IsK
by 84% and g
IsK
by 62%, similar to unstimulated conditions. These results demonstrate that the cAMP pathway is constitutively active in vestibular
dark cells and that the cAMP pathway stimulates transepithelial K+ secretion by increasing IsK channel current rather than by altering another transport pathway.
Received: 9 June 1995/Revised: 17 October 1996 相似文献
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摘要 目的:探讨双歧杆菌MIMBb75通过调节血管活性肠肽(VIP)/环磷酸腺苷(cAMP)/蛋白激酶A(PKA)和哺乳动物雷帕霉素靶蛋白(mTOR)通路对溃疡性结肠炎(UC)小鼠的影响。方法:BALB/c小鼠随机分为正常对照(NC)组、结肠炎模型(UC)组、Mesalazine组和MIMBb75低、高剂量组、MIMBb75高剂量+VIP antagonist组、MIMBb75高剂量+MHY1485组(每组10只),除NC组外均采用5%葡聚糖硫酸钠(DSS)诱导UC模型。治疗结束后,观察小鼠的一般情况及UC疾病活动指数(DAI),检测小鼠肠道组织病理损伤、结肠组织中髓过氧化物酶(MPO)活性、肠道菌群多样性(Chao指数、Shannon指数和Simpson指数)及结肠组织VIP、cAMP、PKA、水通道蛋白3(AQP3)、mTOR、核糖体蛋白S6激酶(S6K1)的mRNA和蛋白水平。结果:与UC组相比,MIMBb75低、高剂量组和Mesalazine组小鼠的体重升高、DAI评分降低,组织病理损伤得到改善,结肠长度增加,MPO活性降低,Chao指数、Shannon指数和Simpson指数升高;VIP、cAMP、PKA、AQP3的mRNA水平和VIP、cAMP、AQP3蛋白的表达及PKA的磷酸化水平升高,mTOR和S6K1 mRNA及其蛋白的磷酸化水平降低(P<0.05)。与MIMBb75高剂量组相比,MIMBb75高剂量+VIP antagonist组VIP、cAMP、PKA、AQP3的mRNA水平和VIP、cAMP、AQP3蛋白的表达及PKA的磷酸化水平降低(P<0.05);MIMBb75高剂量+MHY1485组mTOR和S6K1 mRNA及其蛋白的磷酸化水平升高(P<0.05)。VIP antagonist和MHY1485均能逆转MIMBb75对UC小鼠的保护作用,使其结肠损伤加重,MPO活性增高(P<0.05)。结论:双歧杆菌可改善UC小鼠的结肠损伤,增加肠道菌群的多样性,这可能与激活VIP/cAMP/PKA通路、抑制mTOR通路有关。 相似文献
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An intersection of the cAMP/PKA and two-component signal transduction systems in Dictyostelium. 总被引:2,自引:0,他引:2
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P A Thomason D Traynor G Cavet W T Chang A J Harwood R R Kay 《The EMBO journal》1998,17(10):2838-2845
Terminal differentiation of both stalk and spore cells in Dictyostelium can be triggered by activation of cAMP-dependent protein kinase (PKA). A screen for mutants where stalk and spore cells mature in isolation produced three genes which may act as negative regulators of PKA: rdeC (encoding the PKA regulatory subunit), regA and rdeA. The biochemical properties of RegA were studied in detail. One domain is a cAMP phosphodiesterase (Km approximately 5 microM); the other is homologous to response regulators (RRs) of two-component signal transduction systems. It can accept phosphate from acetyl phosphate in a reaction typical of RRs, with transfer dependent on Asp212, the predicted phosphoacceptor. RegA phosphodiesterase activity is stimulated up to 8-fold by the phosphodonor phosphoramidate, with stimulation again dependent on Asp212. This indicates that phosphorylation of the RR domain activates the phosphodiesterase domain. Overexpression of the RR domain in wild-type cells phenocopies a regA null. We interpret this dominant-negative effect as due to a diversion of the normal flow of phosphates from RegA, thus preventing its activation. Mutation of rdeA is known to produce elevated cAMP levels. We propose that cAMP breakdown is controlled by a phosphorelay system which activates RegA, and may include RdeA. Cell maturation should be triggered when this system is inhibited. 相似文献
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Colletotrichum orbiculare is the causative agent of anthracnose disease on cucurbitaceous plants. Several signaling pathways, including cAMP–PKA and mitogen-activating protein kinase (MAPK) pathways are involved in the infection-related morphogenesis and pathogenicity of C. orbiculare. However, upstream regulators of these pathways for this species remain unidentified. In this study, CoIRA1, encoding RAS GTPase activating protein, was identified by screening the Agrobacterium tumefaciens-mediated transformation (AtMT) mutant, which was defective in the pathogenesis of C. orbiculare. The coira1 disrupted mutant showed an abnormal infection-related morphogenesis and attenuated pathogenesis. In Saccharomyces cerevisiae, Ira1/2 inactivates Ras1/2, which activates adenylate cyclase, leading to the synthesis of cAMP. Increase in the intracellular cAMP levels in coira1 mutants and dominant active forms of CoRAS2 introduced transformants indicated that CoIra1 regulates intracellular cAMP levels through CoRas2. Moreover, the phenotypic analysis of transformants that express dominant active form CoRAS2 in the comekk1 mutant or a dominant active form CoMEKK1 in the coras2 mutant indicated that CoRas2 regulates the MAPK CoMekk1–Cmk1 signaling pathway. The CoRas2 localization pattern in vegetative hyphae of the coira1 mutant was similar to that of the wild-type, expressing a dominant active form of RFP–CoRAS2. Moreover, we demonstrated that bimolecular fluorescence complementation (BiFC) signals between CoIra1 and CoRas2 were detected in the plasma membrane of vegetative hyphae. Therefore, it is likely that CoIra1 negatively regulates CoRas2 in vegetative hyphae. Furthermore, cytological analysis of the localization of CoIraI and CoRas2 revealed the dynamic cellular localization of the proteins that leads to proper assembly of F-actin at appressorial pore required for successful penetration peg formation through the pore. Thus, our results indicated that CoIra1 is involved in infection-related morphogenesis and pathogenicity by proper regulation of cAMP and MAPK signaling pathways through CoRas2. 相似文献
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黄芩甙对发热大鼠下丘脑PGE2和cAMP含量的影响 总被引:18,自引:0,他引:18
目的和方法:PGE2和cAMP是重要的中枢发热介质。为了探讨PGE2和cAMP是否参与了黄芩甙解热的机制,本实验用内毒素(ET)复制大鼠发热模型,观察黄芩甙的解热作用及对大鼠下丘脑中PGE2和cAMP含量的影响。结果:黄芩甙有明显的解热作用,并且翻转ET对下丘脑中PGE2和cAMP含量的影响。相关分析显示,下丘脑中PGE2和cAMP含量的变化与体温变化之间存在明显正相关。结论:黄芩甙可通过抑制下丘脑中PGE2和cAMP含量升高而发挥其解热作用。 相似文献
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Sheriff S Chance WT Iqbal S Rizvi TA Xiao C Kasckow JW Balasubramaniam A 《Peptides》2003,24(2):245-254
Following central administration, neuropeptides that decrease the level of cAMP induce feeding. Conversely, cAMP activating neuropeptides tend to elicit satiety. When the inhibitory effect of neuropeptide Y (NPY) on the hypothalamic cAMP production was blocked by pertussis toxin, the potent orexigenic effect of NPY was lost. These findings suggest that there may be a link between hypothalamic cAMP and the central regulation of food intake. In this report, we show that the injection of the membrane-permeable cAMP agonist, adenosine-3',5'-cyclic monophosphorothioate Sp-isomer (Sp-cAMP), into perifornical hypothalamus (PFH) significantly inhibited schedule-induced and NPY-induced food intake for up to 4h. This inhibitory effect was normalized within 24h. A taste aversion could not be conditioned to Sp-cAMP treatment, suggesting that the anorectic response was not due to malaise. Sp-cAMP administration significantly increased the active protein kinase A (PKA) activity in dorsomedial (DMH) and ventromedial (VMH), but not in lateral (LH) hypothalamus. Consistently, food deprivation lowered, while refeeding normalized endogenous cAMP content in DMH and VMH, but not in LH areas. No significant effect of adenosine-3',5'-cyclic monophosphorothioate Rp-isomer (Rp-cAMP, cAMP antagonist) was observed on hypothalamic PKA activity, schedule-induced, or NPY-induced food intake. These findings suggest that the increase in cAMP level and PKA activity in DMH and VMH areas may trigger a satiety signal. 相似文献
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Suzuki A Ozono K Kubota T Kondou H Tachikawa K Michigami T 《Journal of cellular biochemistry》2008,104(1):304-317
Although the intermittent administration of PTH is known to stimulate the bone formation, the underlying mechanisms are not fully understood. Here we investigated the crosstalk between PTH/cAMP signaling and canonical Wnt signaling using the human osteoblastic cell line Saos-2. Treatment with PTH or forskolin, an activator of adenylate cyclase, facilitated T-cell factor (TCF)-dependent transactivation in a dose-dependent manner, which was abolished by pre-treatment with a PKA inhibitor, H89. Wnt3a and forskolin synergistically increased the TCF-dependent transactivation. Interestingly, intermittent treatment with PTH enhanced the TCF-dependent transactivation more profoundly than continuous treatment. In addition to the effects on TCF-dependent reporter activity, treatment with PTH or forskolin resulted in the increased expression of endogenous targets of Wnts, Wnt-induced secreted protein 2 (WISP2) and naked cuticle 2 (NKD2). We then investigated the convergence point of PTH/cAMP signaling and the canonical Wnt pathway. Western blotting demonstrated that GSK-3beta was rapidly phosphorylated at Ser(9) on treatment with PTH or forskolin, leading to its inactivation. Moreover, overexpression of a constitutively active mutant of GSK-3beta abolished the TCF-dependent transactivation induced by forskolin. On the other hand, overexpression of the Wnt antagonist Dickkopf-1 (DKK1) failed to cancel the effects of forskolin on the canonical Wnt pathway. Interestingly, treatment with Wnt3a markedly reduced the forskolin-induced expression of receptor activator of NF-kappaB ligand (RANKL), a target gene of PTH/cAMP/PKA. These results suggest that cAMP/PKA signaling activates the canonical Wnt pathway through the inactivation of GSK-3beta, whereas Wnt signaling might inhibit bone resorption through a negative impact on RANKL expression in osteoblasts. 相似文献
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Salinity is among the environmental factors that affect plant growth and development and constrain agricultural productivity. Salinity stress triggers increases in cytosolic free Ca2+ concentration ([Ca2+]i) via Ca2+ influx across the plasma membrane. Salinity stress, as well as other stresses, induces the production of reactive oxygen species (ROS). It is well established that ROS also triggers increases in [Ca2+]i. However, the relationship and interaction between salinity stress-induced [Ca2+]i increases and ROS-induced [Ca2+]i increases remain poorly understood. Using an aequorin-based Ca2+ imaging assay we have analyzed [Ca2+]i changes in response to NaCl and H2O2 treatments in Arabidopsis thaliana. We found that NaCl and H2O2 together induced larger increases in [Ca2+]i in Arabidopsis seedlings than either NaCl or H2O2 alone, suggesting an additive effect on [Ca2+]i increases. Following a pre-treatment with either NaCl or H2O2, the subsequent elevation of [Ca2+]i in response to a second treatment with either NaCl or H2O2 was significantly reduced. Furthermore, the NaCl pre-treatment suppressed the elevation of [Ca2+]i seen with a second NaCl treatment more than that seen with a second treatment of H2O2. A similar response was seen when the initial treatment was with H2O2; subsequent addition of H2O2 led to less of an increase in [Ca2+]i than did addition of NaCl. These results imply that NaCl-gated Ca2+ channels and H2O2-gated Ca2+ channels may differ, and also suggest that NaCl- and H2O2-evoked [Ca2+]i may reduce the potency of both NaCl and H2O2 in triggering [Ca2+]i increases, highlighting a feedback mechanism. Alternatively, NaCl and H2O2 may activate the same Ca2+ permeable channel, which is expressed in different types of cells and/or activated via different signaling pathways. 相似文献
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PGE2 and prostacyclin each enhance cAMP synthesis in the osteoblast-like cell line UMR-106. The amount of cAMP induced by PGE2 was 5-7-fold greater than the amount induced by cicaprost or iloprost, stable prostacyclin analogues. Both PGE2 and the two prostacyclin analogues enhanced cAMP synthesis with similar time dependence. The EC50 values of PGE2 and cicaprost were 3 X 10(-6) and 5 x 10(-8) M, respectively. Short-term incubation of the cells with 12-o-tetradecanoylphorbol 13-acetate (TPA) markedly reduced the PGE2-induced cAMP synthesis. In contrast, cells that were incubated with the same concentrations of TPA in the presence of cicaprost or iloprost showed a 1.6-fold increase in cAMP formation. The marked disparity between the cAMP response to cicaprost and PGE2 in the presence of TPA suggests that the two prostanoids induce cAMP synthesis in the UMR-106 cells by interaction with different receptors. These observations support the idea that the osteoblastic UMR-106 cells may express specific prostacyclin receptors and suggest that prostacyclin may have a unique role in osteoblasts. 相似文献