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EA Dukhanina TI Lukyanova EA Romanova V Guerriero NV Gnuchev GP Georgiev DV Yashin LP Sashchenko 《Cell cycle (Georgetown, Tex.)》2015,14(22):3635-3643
PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4+ and CD8+ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response. 相似文献
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The Nitrogen Use Efficiency of C(3) and C(4) Plants : III. Leaf Nitrogen Effects on the Activity of Carboxylating Enzymes in Chenopodium album (L.) and Amaranthus retroflexus (L.) 总被引:6,自引:6,他引:0 下载免费PDF全文
The relationships between leaf nitrogen content per unit area (Na) and (a) the initial slope of the photosynthetic CO2 response curve, (b) activity and amount of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPC), and (c) chlorophyll content were studied in the ecologically similar weeds Chenopodium album (C3) and Amaranthus retroflexus (C4). In both species, all parameters were linearly dependent upon leaf Na. The dependence of the initial slope of the CO2 response of photosynthesis on Na was four times greater in A. retroflexus than in C. album. At equivalent leaf Na contents, C. album had 1.5 to 2.6 times more CO2 saturated Rubisco activity than A. retroflexus. At equal assimilation capacities, C. album had four times the Rubisco activity as A. retroflexus. In A. retroflexus, a one to one ratio between Rubisco activity and photosynthesis was observed, whereas in C. album, the CO2 saturated Rubisco activity was three to four times the corresponding photosynthetic rate. The ratio of PEPC to Rubisco activity in A. retroflexus ranged from four at low Na to seven at high Na. The fraction of organic N invested in carboxylation enzymes increased with increased Na in both species. The fraction of N invested in Rubisco ranged from 10 to 27% in C. album. In A. retroflexus, the fraction of Na invested in Rubisco ranged from 5 to 9% and the fraction invested in PEPC ranged from 2 to 5%. 相似文献
4.
The short-term, in-vivo response to elevated CO2 of ribulose-1,5-bisphosphate carboxylase (RuBPCase, EC 4.1.1.39) activity, and the pool sizes of ribulose 1,5-bisphosphate, 3-phosphoglyceric acid, triose phosphates, fructose 1,6-bisphosphate, glucose 6-phosphate and fructose 6-phosphate in bean were studied. Increasing CO2 from an ambient partial pressure of 360–1600 bar induced a substantial deactivation of RuBPCase at both saturating and subsaturating photon flux densities. Activation of RuBPCase declined for 30 min following the CO2 increase. However, the rate of photosynthesis re-equilibrated within 6 min of the switch to high CO2, indicating that RuBPCase activity did not limit photosynthesis at high CO2. Following a return to low CO2, RuBPCase activation increased to control levels within 10 min. The photosynthetic rate fell immediately after the return to low CO2, and then increased in parallel with the increase in RuBPCase activation to the initial rate observed prior to the CO2 increase. This indicated that RuBPCase activity limited photosynthesis while RuBPCase activation increased. Metabolite pools were temporarily affected during the first 10 min after either a CO2 increase or decrease. However, they returned to their original level as the change in the activation state of RuBPCase neared completion. This result indicates that one role for changes in the activation state of RuBPCase is to regulate the pool sizes of photosynthetic intermediates.Abbreviations and symbols
A
net CO2 assimilation rate
- Ca
ambient CO2 partial pressure
- Ci
intercellular CO2 partial pressure
- CABP
2-carboxyarabinitol 1,5-bisphosphate
- kcat
catalytic turnover rate per RuBPCase molecule
- PFD
photon flux density (400 to 700 nm on an area basis)
- PGA
3-phosphoglyceric acid
- Pi
orthophosphate
- RuBP
ribulose 1,5-bisphosphate
- RuBPCase
ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39) 相似文献
5.
E H Sage 《Biochimie et biologie cellulaire》1992,70(7):579-592
Endothelioma cells expressing the polyoma virus middle T oncogene induced hemangiomas in mice by the recruitment of nonproliferating endothelial cells from host blood vessels (Williams et al. 1989). I now report that SPARC, a Ca(2+)-binding glycoprotein that perturbs cell-matrix interactions and inhibits the endothelial cell cycle, is produced by endothelioma cells and is in part responsible for the alterations in the morphology and growth that occur when nontransformed bovine aortic endothelial cells are cocultured with endothelioma cells. Normal endothelial cells cocultured with two different middle T-positive endothelial cell lines, termed End cells, exhibited changes in shape that were accompanied by the formation of cell clusters. Media conditioned by End cells repressed proliferation of normal endothelial cells, but enhanced that of an established line of murine capillary endothelium. Radiolabeling studies revealed no apparent differences in the profile of proteins secreted by aortic or capillary cells cultured in End cell conditioned media. Characterization of proteins produced by End cells led to the identification of type IV collagen, laminin, entactin, and SPARC as major secreted products. Although SPARC did not affect the morphology of End or capillary cells, it was associated with overt changes in the shape of aortic endothelial cells. Moreover, SPARC and a synthetic peptide from SPARC domain II inhibited the incorporation of [3H]thymidine by aortic cells, but had minimal to no effect on the capillary endothelial cell line. The inhibition of growth exhibited by aortic endothelial cells cultured in End cell conditioned media could be partially reversed by antibodies specific for SPARC and SPARC peptides. These studies indicate a potential role for SPARC in the generation of hemangiomas by End cells in vivo, a process that requires normal (host) endothelial cells to disengage from the extracellular matrix, withdraw from the cell cycle, migrate, and reassociate into the disorganized cellular networks that comprise cavernous and capillary hemangiomas. 相似文献
6.
Culture shock. Selective uptake and rapid release of a novel serum protein by endothelial cells in vitro 总被引:2,自引:0,他引:2
H Sage 《The Journal of biological chemistry》1986,261(15):7082-7092
A novel protein has been purified from fetal calf serum and from serum-free bovine aortic endothelial cell conditioned culture medium. This protein consists of a single polypeptide chain of reduced Mr 70,000 (70K protein) and was separated from bovine serum albumin and other proteins by ion-exchange chromatography and immunoabsorption on Sepharose-coupled anti-70K protein antiserum. The 70K protein was shown to be structurally and immunologically distinct from bovine serum albumin, alpha-fetoprotein, and vitronectin by one- and two-dimensional peptide mapping, amino acid analysis, and enzyme-linked immunosorbent assay and/or immunoblotting. The 70K protein was located in endothelial cell cytoplasmic granules of irregular size and distribution. Metabolic radiolabeling studies showed that the 70K protein was not a biosynthetic product of these cells; its cytoplasmic location was due to a selective uptake from the fetal calf serum in which the cells were initially grown. After subconfluent cultures of endothelial cells were shifted to serum-free medium, nearly 80% of the total 70K protein that was measurable in the medium was released between 0 and 20 min. Moreover, sparse, rapidly proliferating cells released approximately 18-fold more 70K protein within 2 min as compared to dense, nonproliferating cultures. The concentration of 70K protein in fetal calf serum was estimated to be 400-600 micrograms/ml. Proliferating bovine aortic endothelial cells, 24 h after plating at an intermediate density, released approximately 250 pg of 70K protein/cell within the first 20 min after exposure to serum-free conditions. The data provide evidence for a novel protein in serum which is selectively internalized by endothelial cells in vitro and which in turn is released rapidly under conditions such as osmotic imbalance due to serum removal, or during periods of cellular proliferation, conditions which we term "culture shock." 相似文献
7.
Inhibition by forskolin of cytosolic calcium rise, shape change and aggregation in quin2-loaded human platelets 总被引:3,自引:0,他引:3
The adenylate cyclase stimulator forskolin was used to study the inhibitory effects of elevated cAMP on the activation of washed human platelets loaded with the fluorescent Ca2+ indicator quin2. In the presence of 10 microM isobutylmethylxanthine forskolin inhibited rises in [Ca2+]i evoked by thrombin and platelet-activating factor (PAF) due to both Ca2+ influx and release from internal stores with similar potency. Aggregation evoked by thrombin and PAF was suppressed whilst partial shape-change persisted, even in the absence of a measurable rise in [Ca2+]i. Forskolin did not affect the rise in [Ca2+]i evoked by Ca2+ ionophore; aggregation was suppressed but shape-change persisted. 相似文献
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Ribonuclease activity in hepatic nuclei during development 总被引:1,自引:0,他引:1