The Experts below are selected from a list of 4515 Experts worldwide ranked by ideXlab platform
Pinchas Cohen - One of the best experts on this subject based on the ideXlab platform.
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type iα collagen is an igfbp 3 binding protein
Growth Hormone & Igf Research, 2003Co-Authors: Stuart A Weinzimer, Tara Beers Gibson, Desmond Mascarenhas, Pinchas CohenAbstract:Abstract Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) possesses both growth-inhibitory and -potentiating effects on cells, which are independent of IGF action and mediated through specific IGFBP-3 binding proteins/receptors located at the cell membrane, cytosol, or nuclear compartments as well as in the extracellular matrix. We here characterized type Iα collagen as one of these IGFBP-3 binding proteins. Human serum was fractionated over an IGFBP-3 affinity column, and bands at 70–100 kDa were eluted as IGFBP-3 ligands. The 100-kDa band was extracted, subjected to N-terminal amino acid sequencing, and identified through database searching as the N-terminal chain of type Iα collagen protein. In a separate screening approach, using a yeast two-hybrid system, we cloned the type Iα collagen cDNA from a human liver cDNA library as an IGFBP-3 protein partner. Anti-IGFBP-3 antibodies co-immunoprecipitated type Iα collagen and IGFBP-3 from the conditioned media of human fibroblasts and vice versa. We demonstrated through ligand dot blot analysis that type Iα collagen binds IGFBP-3. IGFBP-3 mutants, with altered sequence at the nuclear localization sequence, bound type Iα collagen poorly. Western immunoblot showed that type Iα collagen binds only IGFBP-3 but not IGF-I, suggesting an IGF-I-independent mechanism of this interaction. Physiological effects of IGFBP-3–collagen interactions may include modulation of cell adhesion and migration.
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direct functional interactions between insulin like growth factor binding protein 3 and retinoid x receptor α regulate transcriptional signaling and apoptosis
Journal of Biological Chemistry, 2000Co-Authors: Stuart A Weinzimer, David R Powell, John L Clifford, Jonathan M Kurie, Pinchas CohenAbstract:Abstract Insulin-like growth factor-binding protein (IGFBP)-3 regulates apoptosis in an IGF-independent fashion and has been shown to localize to nuclei. We cloned the nuclear receptor retinoid X receptor-α(RXR-α) as an IGFBP-3 protein partner in a yeast two-hybrid screen. Multiple methodologies showed that IGFBP-3 and RXR-α bind each other within the nucleus. IGFBP-3-induced apoptosis was abolished in RXR-α-knockout cells. IGFBP-3 and RXR ligands were additive in inducing apoptosis in prostate cancer cells. IGFBP-3 enhanced RXR response element and inhibited RARE signaling. Thus, RXR-α-IGFBP-3 interaction leads to modulation of the transcriptional activity of RXR-α and is essential for mediating the effects of IGFBP-3 on apoptosis.
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insulin like growth factor igf binding protein 3 induces apoptosis and mediates the effects of transforming growth factor β1 on programmed cell death through a p53 and igf independent mechanism
Journal of Biological Chemistry, 1997Co-Authors: Roopmathy Rajah, Barbara Valentinis, Pinchas CohenAbstract:Abstract Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) is known to block IGF action and inhibit cell growth. IGFBP-3 is thought to act by sequestering free IGFs or, possibly, act via a novel IGF-independent mechanism. Supporting its role as a primary growth inhibitor, IGFBP-3 production has been shown to be increased by cell growth-inhibitory agents, such as transforming growth factor-β (TGF-β), and the tumor suppressor gene p53. In this paper, we demonstrate, for the first time, a novel function of IGFBP-3 as an apoptosis-inducing agent and show that this action is mediated through an IGF·IGF receptor-independent pathway. In the p53 negative prostate cancer cell line, PC-3, the addition of recombinant IGFBP-3 resulted in a dose-dependent induction of apoptosis.125I-IGFBP-3 bound with high affinity to specific proteins in PC-3 cell lysates and plasma membrane preparations. These membrane-associated molecules may serve as receptors that mediate the direct effect of IGFBP-3 on apoptosis. In addition, in an IGF receptor-negative mouse fibroblast cell line, treatment with recombinant IGFBP-3 as well as transfection of the IGFBP-3 gene induced apoptosis, suggesting that neither IGFs nor IGF receptors are required for this action. Furthermore, treatment with TGF-β1, a known apoptosis-inducing agent, resulted in the induction of IGFBP-3 expression 6–12 h before the onset of apoptosis. This effect of TGF-β1 was prevented by co-treatment with IGFBP-3-neutralizing antibodies or IGFBP-3-specific antisense thiolated oligonucleotides. These findings suggest that IGFBP-3 induces apoptosis through a novel pathway independent of either p53 or the IGF·IGF receptor-mediated cell survival pathway and that IGFBP-3 mediates TGF-β1 induced apoptosis in PC-3 cells.
Jinlin Zhou - One of the best experts on this subject based on the ideXlab platform.
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immunoglobulin g binding protein IGBP from rhipicephalus haemaphysaloides identification expression and binding specificity
Parasitology Research, 2014Co-Authors: Haiyan Gong, Houshuang Zhang, Yongzhi Zhou, Xuenan Xuan, Hiroshi Suzuki, Jinlin ZhouAbstract:As the second most important human ectoparasite, ranked only after mosquitoes, the tick threatens the development of husbandry and even the health of humans worldwide. Immunoglobulin G binding proteins (IGBPs) are considered to be the major factors used by ticks to evade the host immune system and the damage caused by host antibodies. In this study, an IGBP-MB homologue was identified in the tick Rhipicephalus haemaphysaloides, which was predominantly detected in the salivary glands and hemolymph of male ticks. Recombinant IGBP (rIGBP/His) displayed significant binding activity to IgGs from rabbits and pigs, and bound to the F(ab)’2 but not the Fc fragment of rabbit IgG. Although the silencing of IGBP expression in ticks had no obvious effect on their blood-feeding and subsequent oviposition, antibodies raised to rIGBP/GST reduced the replete body weight (218.9 ± 20 mg in the control group vs. 142.5 ± 43.3 mg in the test group, P < 0.05 by Student’s t test) and increased the mortality of the ticks. This study extends our understanding of the immunoevasive function of IGBPs and is a step towards the development of a vaccine against ticks.
Al A. Bitar - One of the best experts on this subject based on the ideXlab platform.
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SMOS-IC: A revised SMOS product based on a new effective scattering albedo and soil roughness parameterization
2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), 2017Co-Authors: R. Fernandez-moran, J.-p. Wigneron, G. De Lannoy, E. Lopez-baeza, M. Parrens, A. Mialon, A. Mahmoodi, A. Al-yaari, S. Bircher, Al A. BitarAbstract:This study presents a new SMOS (Soil Moisture and Ocean Salinity) soil moisture (SM) product based on a different scattering albedo and soil roughness parameterization: the SMOS-IC (SMOS INRA-CESBIO) data set. In this study, several parameterizations of the vegetation and soil roughness parameters (ω, HR and NRP, P = H, V) were tested and the retrieved SM was compared against in situ observations obtained from the International Soil Moisture Network (ISMN). Firstly, values of ω = 0.10, HR = 0.4 and NRP = -1 (P = H, V) were found globally. Secondly, a calibration of these parameters was obtained for the different land cover categories of the International Geosphere-Biosphere Programme (IGBP) scheme. Depending on the IGBP land cover class, values of ω and HR varied, respectively, in the ranges 0.08-0.12 and 0.1-0.5. The IGBP-based calibration is currently used in the SMOS-IC product algorithm. Using as reference the ISMN sites, a better performance of the SMOS-IC product over the operational SMOSL3 (SMOS level 3) SM product was found: R = 0.62, bias = -0.019 m3/m3, ubRMSE = 0.061 m3/m3 for SMOS-IC; against R = 0.54, bias = -0.037 m3/m3 and ubRMSE = 0.069 m3/m3 for SMOSL3.
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IGARSS - SMOS-IC: A revised SMOS product based on a new effective scattering albedo and soil roughness parameterization
2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), 2017Co-Authors: R. Fernandez-moran, J.-p. Wigneron, G. De Lannoy, E. Lopez-baeza, M. Parrens, A. Mialon, A. Mahmoodi, A. Al-yaari, S. Bircher, Al A. BitarAbstract:This study presents a new SMOS (Soil Moisture and Ocean Salinity) soil moisture (SM) product based on a different scattering albedo and soil roughness parameterization: the SMOS-IC (SMOS INRA-CESBIO) data set. In this study, several parameterizations of the vegetation and soil roughness parameters (ω, H R and N RP , P = H, V) were tested and the retrieved SM was compared against in situ observations obtained from the International Soil Moisture Network (ISMN). Firstly, values of ω = 0.10, H R = 0.4 and N RP = −1 (P = H, V) were found globally. Secondly, a calibration of these parameters was obtained for the different land cover categories of the International Geosphere-Biosphere Programme (IGBP) scheme. Depending on the IGBP land cover class, values of ω and H R varied, respectively, in the ranges 0.08–0.12 and 0.1–0.5. The IGBP-based calibration is currently used in the SMOS-IC product algorithm. Using as reference the ISMN sites, a better performance of the SMOS-IC product over the operational SMOSL3 (SMOS level 3) SM product was found: R = 0.62, bias = −0.019 m3/m3, ubRMSE = 0.061 m3/m3 for SMOS-IC; against R = 0.54, bias = −0.037 m3/m3 and ubRMSE = 0.069 m3/m3 for SMOSL3.
Terrance J. Beveridge - One of the best experts on this subject based on the ideXlab platform.
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haemophilus somnus immunoglobulin binding proteins and surface fibrils
Infection and Immunity, 1997Co-Authors: Lynette B. Corbeil, F D Bastidacorcuera, Terrance J. BeveridgeAbstract:The high-molecular-weight (HMW) immunoglobulin binding proteins (IGBPs) of Haemophilus somnus and a 76-kDa surface protein (p76) are found in serum-resistant virulent strains but not in several serum-sensitive strains from asymptomatic carriers. For the first time, p76 was shown to be an IGBP also. This was done by competitive inhibition studies with affinity-purified antidinitrophenol (anti-DNP) and DNP to ensure that binding was not antigen specific. The HMW IGBPs, but not the p76 IGBP, were partially purified from concentrated culture supernatant in detergent by fluid-phase liquid chromatography with a gel filtration column. Membrane extraction studies showed that p76 predominated in the Sarkosyl-soluble fraction of the bacterial cell pellet. Since integral outer membrane (OM) proteins are Sarkosyl insoluble, this is consistent with our previous finding that implicated p76 as a peripheral OM protein. The HMW IGBPs were found predominantly in the Sarkosyl-soluble fraction of the culture supernatant. This suggests that they were not integral membrane proteins and that their presence in the supernatant was not due to OM blebbing. We then showed that two IGBP-positive serum-resistant virulent strains have a surface fibrillar network but that two IGBP-negative serum-sensitive H. somnus strains from asymptomatic preputial carriers do not. Fibrils on the surfaces of IGBP+ strains bound gold-labelled bovine immunoglobulin G2 (IgG2) anti-DNP, indicating that these fibrils have IgG2 binding activity. Therefore, this study shows that H. somnus has two IGBPs, including a peripheral membrane protein and a fibrillar surface network.
Yichen Wang - One of the best experts on this subject based on the ideXlab platform.
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usability study to assess the IGBP land cover classification for singapore
Remote Sensing, 2017Co-Authors: Nanki Sidhu, Edzer Pebesma, Yichen WangAbstract:Our research focuses on assessing the usability of the International Geosphere Biosphere Programme (IGBP) classification scheme provided in the MODIS MCD12Q1-1 dataset for assessing the land cover of the city-state, Singapore. We conducted a user study with responses from 33 users by providing them with Google Earth images from different parts of Singapore, asking survey-takers to classify these images according to their understanding by the IGBP definitions provided. We also conducted interviews with experts from major governmental agencies working with satellite imagery, which highlighted the need for a detailed land classification for Singapore. In addition to the qualitative analysis of the IGBP land classification scheme, we carried out a validation of the MCD12Q1-1 remote sensing product against SPOT-5 imagery for our study area. The user study revealed that survey-takers were able to correctly classify urban areas, as well as densely forested areas. Misclassifications between Cropland and Mixed Forest classes were highest and were attributed by users to the broad terminology of the IGBP of the two land cover class definitions. For the accuracy assessment, we obtained validation points using weighted and unweighted stratified sampling. The overall classification accuracy for all 17 IGBP land classes is 62%. Upon selecting only the four most occurring IGBP land classes in Singapore, the classification accuracy improved to 71%. Validation of the MCD12Q1-1 against ground truth for Singapore revealed less-common land classes that may be of importance in a global context but are sources of error when the same product is applied at a smaller scale. Combining the user study with the accuracy assessment gives a comprehensive overview of the challenges associated with using global-level land cover data to derive localized land cover information specifically for smaller land masses like Singapore.
