LIVIVO - Search results -

Search results

Result 1 - 10 of total 51

Search options

Book ; Online: DeGroot-based opinion formation under a global steering mechanism

Conjeaud, Ivan / Lorenz-Spreen, Philipp / Kalogeratos, Argyris

2022

Abstract: This paper investigates how interacting agents arrive to a consensus or a polarized state. We study the opinion formation process under the effect of a global steering mechanism (GSM), which aggregates the opinion-driven stochastic agent states at the ... ...

Abstract	This paper investigates how interacting agents arrive to a consensus or a polarized state. We study the opinion formation process under the effect of a global steering mechanism (GSM), which aggregates the opinion-driven stochastic agent states at the network level and feeds back to them a form of global information. We also propose a new two-layer agent-based opinion formation model, called GSM-DeGroot, that captures the coupled dynamics between agent-to-agent local interactions and the GSM's steering effect. This way, agents are subject to the effects of a DeGroot-like local opinion propagation, as well as to a wide variety of possible aggregated information that can affect their opinions, such as trending news feeds, press coverage, polls, elections, etc. Contrary to the standard DeGroot model, our model allows polarization to emerge by letting agents react to the global information in a stubborn differential way. Moreover, the introduced stochastic agent states produce event stream dynamics that can fit to real event data. We explore numerically the model dynamics to find regimes of qualitatively different behavior. We also challenge our model by fitting it to the dynamics of real topics that attracted the public attention and were recorded on Twitter. Our experiments show that the proposed model holds explanatory power, as it evidently captures real opinion formation dynamics via a relatively small set of interpretable parameters. Comment: IEEE Transactions on Computational Social Systems. 17 double-column pages, 9 figures, 4 tables
Keywords	Computer Science - Social and Information Networks ; Computer Science - Computers and Society ; Computer Science - Multiagent Systems ; 68U35 ; 91Cxx ; 90-10 ; I.6 ; H.4 ; J.4 ; K.4.2
Subject code	006
Publishing date	2022-10-21
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Effects of phosphorus and ectomycorrhiza on maritime pine seedlings (Pinus pinaster).

Conjeaud, C / Scheromm, P / Mousain, D

The New phytologist

2018 Volume 133, Issue 2, Page(s) 345–351

Abstract: The purpose of this study was to determine how ectomycorrhizal infection and phosphorus nutrition affect biomass, photosynthesis and root respiration in the host plant. Maritime pine (Pinus pinaster Soland. in Ait.) seedlings grown in containers filled ... ...

Abstract	The purpose of this study was to determine how ectomycorrhizal infection and phosphorus nutrition affect biomass, photosynthesis and root respiration in the host plant. Maritime pine (Pinus pinaster Soland. in Ait.) seedlings grown in containers filled with perlite-vermiculite were inoculated with the ectomycorrhizal fungus Hebeloma cylindrosporum (strain D3.25.9) and given 0 or 0.5 mM phosphate in the nutrient solution. Hebeloma cylindrosporum infection increased net photosynthesis and root respiration rates compared with those of non-mycorrhizal plants, but there was an accompanying 35 % depression in growth. The addition of phosphorus to non-mycorrhizal plants induced a rise in tissue phosphorus content which made them similar m that respect to mycorrhizal plants but did not result in increased photosynthesis. The nitrogen content of mycorrhizal plants was, moreover, lower than that of the control group. The data recorded were consistent with the photosynthate source-sink hypothesis. The increase in fixed carbon in mycorrhizal plants was unable to compensate for the increased carbon cost of the mycorrhizal root system.
Language	English
Publishing date	2018-04-12
Publishing country	England
Document type	Journal Article
ZDB-ID	208885-x
ISSN	1469-8137 ; 0028-646X
ISSN (online)	1469-8137
ISSN	0028-646X
DOI	10.1111/j.1469-8137.1996.tb01901.x
Database	MEDical Literature Analysis and Retrieval System OnLINE

Full text online

Accessible to users with ZB MED library card

In stock of ZB MED Bonn / Germany

Z 868: Show issues

Order via subito

This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Details ▾

Article: Electron Transfer in the Photosynthetic Membrane: Influence of PH and Surface Potential on the P-680 Reduction Kinetics.

Conjeaud, H / Mathis, P

Biophysical journal

2009 Volume 49, Issue 6, Page(s) 1215–1221

Abstract: ... chloroplasts (Conjeaud, H., and P. Mathis, 1980, Biochim. Biophys. Acta, 590:353-359) a fast phase of P-680 ...

Abstract	The primary electron donor P-680 of the Photosystem-II reaction center was photoxidized by a short flash given after dark adaptation of photosynthetic membranes in which oxygen evolution was inhibited. The P-680(+) reduction rate was measured under different conditions of pH and salt concentration by following the recovery of the absorption change at 820 nm. As previously reported for Tris-washed chloroplasts (Conjeaud, H., and P. Mathis, 1980, Biochim. Biophys. Acta, 590:353-359) a fast phase of P-680(+) reduction slows down as the bulk pH decreases. When salt concentration increases, this fast phase becomes faster for pH above 4.5-5 and slower below. A quantitative interpretation is proposed in which the P-680(+) reduction kinetics by the secondary electron donor Z are controlled by the local pH. This pH, at the membrane level, can be calculated using the Gouy-Chapman theory. A good fit of the results requires to assume that the surface charge density of the inside of the membrane, near the Photosystem-II reaction center, is positive at low pH values and becomes negative as the pH increases, with a local isoelectric point approximately 4.8. These results lead us to propose a functional scheme in which a pH-dependent proton release is coupled to the electron transfer between secondary and primary donors of Photosystem-II. The H(+)/e ratio varies from 1 at low pH to 0 at high pH, with a real pK approximately 6.5 for the protonatable species.
Language	English
Publishing date	2009-05-08
Publishing country	United States
Document type	Journal Article
ZDB-ID	218078-9
ISSN	1542-0086 ; 0006-3495
ISSN (online)	1542-0086
ISSN	0006-3495
DOI	10.1016/S0006-3495(86)83750-X
Database	MEDical Literature Analysis and Retrieval System OnLINE

Full text online

Accessible to users with ZB MED library card

In stock of ZB MED Cologne/Königswinter

Zs.A 235: Show issues			Location: Je nach Verfügbarkeit (siehe Angabe bei Bestand) bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular Jg. 1995 - 2021: Lesesall (1.OG) ab Jg. 2022: Lesesaal (EG)
Zs.MO 2: Show issues

Order via subito

Details ▾

Article ; Online: Segregative clustering of Lo and Ld membrane microdomains induced by local pH gradients in GM1-containing giant vesicles: a lipid model for cellular polarization.

Staneva, Galya / Puff, Nicolas / Seigneuret, Michel / Conjeaud, Hélène / Angelova, Miglena I

Langmuir : the ACS journal of surfaces and colloids

2012 Volume 28, Issue 47, Page(s) 16327–16337

Abstract: Several cell polarization processes are coupled to local pH gradients at the membrane surface. We have investigated the involvement of a lipid-mediated effect in such coupling. The influence of lateral pH gradients along the membrane surface on lipid ... ...

Abstract	Several cell polarization processes are coupled to local pH gradients at the membrane surface. We have investigated the involvement of a lipid-mediated effect in such coupling. The influence of lateral pH gradients along the membrane surface on lipid microdomain dynamics in giant unilamellar vesicles containing phosphatidylcholine, sphingomyelin, cholesterol, and the ganglioside GM1 was studied. Lo/Ld phase separation was generated by photosensitization. A lateral pH gradient was established along the external membrane surface by acid local microinjection. The gradient promotes the segregation of microdomains: Lo domains within an Ld phase move toward the higher pH side, whereas Ld domains within an Lo phase move toward the lower pH side. This results in a polarization of the vesicle membrane into Lo and Ld phases poles in the axis of the proton source. A secondary effect is inward tubulation in the Ld phase. None of these processes occurs without GM1 or with the analog asialo-GM1. These are therefore related to the acidic character of the GM1 headgroup. LAURDAN fluorescence experiments on large unilamellar vesicles indicated that, with GM1, an increase in lipid packing occurs with decreasing pH, attributed to the lowering of repulsion between GM1 molecules. Packing increase is much higher for Ld phase vesicles than for Lo phase vesicles. It is proposed that the driving forces for domain vectorial segregative clustering and vesicle polarization are related to such differences in packing variations with pH decrease between the Lo and Ld phases. Such pH-driven domain clustering might play a role in cellular membrane polarization processes in which local lateral pH gradients are known to be important, such as migrating cells and epithelial cells.
MeSH term(s)	2-Naphthylamine/analogs & derivatives ; 2-Naphthylamine/chemistry ; Cell Polarity ; Fluorescent Dyes/chemistry ; G(M1) Ganglioside/chemistry ; Hydrogen-Ion Concentration ; Laurates/chemistry ; Membrane Microdomains/chemistry ; Microinjections ; Unilamellar Liposomes/chemistry
Chemical Substances	Fluorescent Dyes ; Laurates ; Unilamellar Liposomes ; G(M1) Ganglioside (37758-47-7) ; asialo GM1 ganglioside (71012-19-6) ; 2-Naphthylamine (CKR7XL41N4) ; laurdan (Y97FBL93VW)
Language	English
Publishing date	2012-11-27
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2005937-1
ISSN	1520-5827 ; 0743-7463
ISSN (online)	1520-5827
ISSN	0743-7463
DOI	10.1021/la3031107
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Article ; Online: Thirty-femtogram detection of iron in mammalian cells.

Galimard, Aymeric / Safi, Malak / Ould-Moussa, Nawel / Montero, David / Conjeaud, Hélène / Berret, Jean-François

Small (Weinheim an der Bergstrasse, Germany)

2012 Volume 8, Issue 13, Page(s) 2036–2044

Abstract: Inorganic nanomaterials and particles with enhanced optical, mechanical, or magnetic attributes are currently being developed for a wide range of applications. Safety issues have developed however concerning their potential cyto- and genotoxicity. For in ...

Abstract	Inorganic nanomaterials and particles with enhanced optical, mechanical, or magnetic attributes are currently being developed for a wide range of applications. Safety issues have developed however concerning their potential cyto- and genotoxicity. For in vivo and in vitro experimentations, recent developments have heightened the need for simple and facile methods to measure the amount of nanoparticles taken up by cells or tissues. In this work, a rapid and highly sensitive method for quantifying the uptake of iron oxide nanoparticles in mammalian cells is reported. The approach exploits the digestion of incubated cells with concentrated hydrochloric acid reactant and a colorimetric-based UV-visible absorption technique. The technique allows the detection of iron in cells over 4 decades in masses from 0.03 to 300 picograms per cell. Applied on particles of different surface chemistry and sizes, the protocol demonstrates that the coating is the key parameter in the nanoparticle/cell interactions. The data are corroborated by scanning and transmission electron microscopy, and the results stress the importance of resiliently adsorbed nanoparticles at the plasma membrane.
MeSH term(s)	Animals ; Iron/metabolism ; Mice ; NIH 3T3 Cells ; Nanoparticles/chemistry ; Spectrum Analysis/methods
Chemical Substances	Iron (E1UOL152H7)
Language	English
Publishing date	2012-07-09
Publishing country	Germany
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1613-6829
ISSN (online)	1613-6829
DOI	10.1002/smll.201102356
Database	MEDical Literature Analysis and Retrieval System OnLINE

Full text online

Accessible to users with ZB MED library card

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Details ▾
- Full text online
- Order with fees

Article ; Online: In vitro toxicity of nanoceria: effect of coating and stability in biofluids.

Ould-Moussa, Nawel / Safi, Malak / Guedeau-Boudeville, Marie-Alice / Montero, David / Conjeaud, Hélène / Berret, Jean-François

Nanotoxicology

2014 Volume 8, Issue 7, Page(s) 799–811

Abstract: Due to the increasing use of nanometric cerium oxide in applications, concerns about the toxicity of these particles have been raised and have resulted in a large number of studies. We report here on the interactions between 7 nm anionically charged ... ...

Abstract	Due to the increasing use of nanometric cerium oxide in applications, concerns about the toxicity of these particles have been raised and have resulted in a large number of studies. We report here on the interactions between 7 nm anionically charged cerium oxide particles and living mammalian cells. By a modification of the particle coating including low-molecular weight ligands and polymers, two generic behaviours are compared: particles coated with citrate ions that precipitate in biofluids and particles coated with poly(acrylic acid) that are stable and remain nanometric. We find that nanoceria covered with both coating agents are taken up by mouse fibroblasts and localized into membrane-bound compartments. However, flow cytometry and electron microscopy reveal that as a result of their precipitation, citrate-coated particles interact more strongly with cells. At cerium concentration above 1 mM, only citrate-coated nanoceria (and not particles coated with poly(acrylic acid)) display toxicity and moderate genotoxicity. The results demonstrate that the control of the surface chemistry of the particles and its ability to prevent aggregation can affect the toxicity of nanomaterials.
MeSH term(s)	Animals ; Cell Survival/drug effects ; Cerium/chemistry ; Cerium/toxicity ; Colloids/chemistry ; DNA Damage/drug effects ; Drug Stability ; Fibroblasts/chemistry ; Fibroblasts/cytology ; Fibroblasts/drug effects ; Metal Nanoparticles/chemistry ; Metal Nanoparticles/toxicity ; Mice ; Models, Biological ; NIH 3T3 Cells ; Particle Size ; Reactive Oxygen Species/analysis ; Reactive Oxygen Species/metabolism
Chemical Substances	Colloids ; Reactive Oxygen Species ; Cerium (30K4522N6T) ; ceric oxide (619G5K328Y)
Language	English
Publishing date	2014-11
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2237988-5
ISSN	1743-5404 ; 1743-5390
ISSN (online)	1743-5404
ISSN	1743-5390
DOI	10.3109/17435390.2013.831501
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Article ; Online: Cell sorting by endocytotic capacity in a microfluidic magnetophoresis device.

Robert, Damien / Pamme, Nicole / Conjeaud, Hélène / Gazeau, Florence / Iles, Alexander / Wilhelm, Claire

Lab on a chip

2011 Volume 11, Issue 11, Page(s) 1902–1910

Abstract: Magnetically labelled cells are finding a wealth of applications for in vitro analysis as well as in vivo treatments. Sorting of cells into subpopulations based on their magnetite loading is an important step in such procedures. Here, we study the ... ...

Abstract	Magnetically labelled cells are finding a wealth of applications for in vitro analysis as well as in vivo treatments. Sorting of cells into subpopulations based on their magnetite loading is an important step in such procedures. Here, we study the sorting of monocytes and macrophages which internalise nanoparticles to different extents based on their endocytotic capacity. Macrophages featured a high endocytotic activity and were found to internalise between 4 and 60 pg of iron per cell. They were successfully sorted into five subpopulations of narrow iron loading distributions via on-chip free-flow magnetophoresis, thus demonstrating the potential of sorting of relatively similarly loaded cells. Monocytes featured a low endocytotic capacity and took on 1 to 4 pg of iron per cell. Mixtures of monocytes and macrophages were successfully sorted within the free-flow magnetophoresis chip and good purity (>88%), efficacy (>60%) and throughput (from 10 to 100 cells s(-1)) could be achieved. The introduced method constitutes a viable tool for studies of endocytotic capacity and sorting/selection of cells based on this functionality.
MeSH term(s)	Cell Movement ; Cell Separation/methods ; Cells, Cultured ; Endocytosis ; Flow Cytometry ; Humans ; Iron/analysis ; Macrophages/cytology ; Microfluidic Analytical Techniques/methods ; Monocytes/cytology ; Nanoparticles/chemistry
Chemical Substances	Iron (E1UOL152H7)
Language	English
Publishing date	2011-06-07
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2056646-3
ISSN	1473-0189 ; 1473-0197
ISSN (online)	1473-0189
ISSN	1473-0197
DOI	10.1039/c0lc00656d
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Article ; Online: Making a tool of an artifact: the application of photoinduced Lo domains in giant unilamellar vesicles to the study of Lo/Ld phase spinodal decomposition and its modulation by the ganglioside GM1.

Staneva, Galya / Seigneuret, Michel / Conjeaud, Hélène / Puff, Nicolas / Angelova, Miglena I

Langmuir : the ACS journal of surfaces and colloids

2011 Volume 27, Issue 24, Page(s) 15074–15082

Abstract: Electroformed giant unilamellar vesicles containing liquid-ordered Lo domains are important tools for the modeling of the physicochemical properties and biological functions of lipid rafts. Lo domains are usually imaged using fluorescence microscopy of ... ...

Abstract	Electroformed giant unilamellar vesicles containing liquid-ordered Lo domains are important tools for the modeling of the physicochemical properties and biological functions of lipid rafts. Lo domains are usually imaged using fluorescence microscopy of differentially phase-partionioning membrane-embedded probes. Recently, it has been shown that these probes also have a photosensitizing effect that leads to lipid chemical modification during the fluorescence microscopy experiments. Moreover, the lipid reaction products are able as such to promote Lo microdomain formation, leading to potential artifacts. We show here that this photoinduced effect can also purposely be used as a new approach to study Lo microdomain formation in giant unilamellar vesicles. Photosensitized lipid modification can promote Lo microdomain appearance and growth uniformly and on a faster time scale, thereby yielding new information on such processes. For instance, in egg phosphatidylcholine/egg sphingomyelin/cholesterol 50:30:20 (mol/mol) giant unilamellar vesicles, photoinduced Lo microdomain formation appears to occur by the rarely observed spinodal decomposition process rather than by the common nucleation process usually observed for Lo domain formation in bilayers. Moreover, temperature and the presence of the ganglioside GM1 have a profound effect on the morphological outcome of the photoinduced phase separation, eventually leading to features such as bicontinuous phases, phase percolation inversions, and patterns evoking double phase separations. GM1 also has the effect of destabilizing Lo microdomains. These properties may have consequences for Lo nanodomains stability and therefore for raft dynamics in biomembranes. Our data show that photoinduced Lo microdomains can be used to obtain new data on fast raft-mimicking processes in giant unilamellar vesicles.
MeSH term(s)	Animals ; Artifacts ; Biomimetics/methods ; Chickens ; Cholesterol/chemistry ; Cholesterol/metabolism ; G(M1) Ganglioside/chemistry ; G(M1) Ganglioside/pharmacology ; Image Processing, Computer-Assisted ; Kinetics ; Light ; Lipid Bilayers/chemistry ; Lipid Bilayers/metabolism ; Membrane Microdomains/chemistry ; Membrane Microdomains/drug effects ; Membrane Microdomains/metabolism ; Membrane Microdomains/radiation effects ; Microscopy, Fluorescence ; Microscopy, Video ; Phosphatidylcholines/chemistry ; Phosphatidylcholines/metabolism ; Photochemical Processes/radiation effects ; Sphingomyelins/chemistry ; Sphingomyelins/metabolism ; Temperature ; Time Factors ; Unilamellar Liposomes/chemistry ; Unilamellar Liposomes/metabolism
Chemical Substances	Lipid Bilayers ; Phosphatidylcholines ; Sphingomyelins ; Unilamellar Liposomes ; G(M1) Ganglioside (37758-47-7) ; Cholesterol (97C5T2UQ7J)
Language	English
Publishing date	2011-12-20
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2005937-1
ISSN	1520-5827 ; 0743-7463
ISSN (online)	1520-5827
ISSN	0743-7463
DOI	10.1021/la203101y
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Article ; Online: The effects of aggregation and protein corona on the cellular internalization of iron oxide nanoparticles.

Safi, M / Courtois, J / Seigneuret, M / Conjeaud, H / Berret, J-F

Biomaterials

2011 Volume 32, Issue 35, Page(s) 9353–9363

Abstract: Engineered inorganic nanoparticles are essential components in the development of nanotechnologies. For applications in nanomedicine, particles need to be functionalized to ensure a good dispersibility in biological fluids. In many cases however, ... ...

Abstract	Engineered inorganic nanoparticles are essential components in the development of nanotechnologies. For applications in nanomedicine, particles need to be functionalized to ensure a good dispersibility in biological fluids. In many cases however, functionalization is not sufficient: the particles become either coated by a corona of serum proteins or precipitate out of the solvent. In the present paper, we show that by changing the coating of iron oxide nanoparticles from a low-molecular weight ligand (citrate ions) to small carboxylated polymers (poly(acrylic acid)), the colloidal stability of the dispersion is improved and the adsorption/internalization of iron toward living mammalian cells is profoundly affected. Citrate-coated particles are shown to destabilize in all fetal-calf-serum based physiological conditions tested, whereas the polymer coated particles exhibit an outstanding dispersibility as well as a structure devoid of protein corona. The interactions between nanoparticles and human lymphoblastoid cells are investigated by transmission electron microscopy and flow cytometry. Two types of nanoparticle/cell interactions are underlined. Iron oxides are found either adsorbed on the cellular membranes, or internalized into membrane-bound endocytosis compartments. For the precipitating citrate-coated particles, the kinetics of interactions reveal a massive and rapid adsorption of iron oxide on the cell surfaces. The quantification of the partition between adsorbed and internalized iron was performed from the cytometry data. The results highlight the importance of resilient adsorbed nanomaterials at the cytoplasmic membrane.
MeSH term(s)	Acrylic Resins/chemistry ; Adsorption/drug effects ; Blood Proteins/chemistry ; Blood Proteins/metabolism ; Citrates/chemistry ; Colloids ; Culture Media/pharmacology ; Endocytosis/drug effects ; Ferric Compounds/metabolism ; Flow Cytometry ; Humans ; Hydrodynamics ; Light ; Molecular Weight ; Nanoparticles/chemistry ; Nanoparticles/ultrastructure ; Protein Binding ; Protein Structure, Quaternary ; Scattering, Radiation
Chemical Substances	Acrylic Resins ; Blood Proteins ; Citrates ; Colloids ; Culture Media ; Ferric Compounds ; ferric oxide (1K09F3G675) ; carbopol 940 (4Q93RCW27E)
Language	English
Publishing date	2011-12
Publishing country	Netherlands
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	603079-8
ISSN	1878-5905 ; 0142-9612
ISSN (online)	1878-5905
ISSN	0142-9612
DOI	10.1016/j.biomaterials.2011.08.048
Database	MEDical Literature Analysis and Retrieval System OnLINE

Full text online

Accessible to users with ZB MED library card

In stock of ZB MED Cologne/Königswinter

Zs.B 2371: Show issues

Location:
Je nach Verfügbarkeit (siehe Angabe bei Bestand)
bis Jg. 2021: Bestellungen von Artikeln über das Online-Bestellformular
ab Jg. 2022: Lesesaal (EG)

Order via subito

Details ▾

Article ; Online: Metastasis suppressor tetraspanin CD82/KAI1 regulates ubiquitylation of epidermal growth factor receptor.

Odintsova, Elena / van Niel, Guillaume / Conjeaud, Hélène / Raposo, Graça / Iwamoto, Ryo / Mekada, Eisuke / Berditchevski, Fedor

The Journal of biological chemistry

2013 Volume 288, Issue 36, Page(s) 26323–26334

Abstract: Ligand-induced ubiquitylation of EGF receptor (EGFR) is an important regulatory mechanism that controls endocytic trafficking of the receptor and its signaling potential. Here we report that tetraspanin CD82/KAI1 specifically suppresses ubiquitylation of ...

Abstract	Ligand-induced ubiquitylation of EGF receptor (EGFR) is an important regulatory mechanism that controls endocytic trafficking of the receptor and its signaling potential. Here we report that tetraspanin CD82/KAI1 specifically suppresses ubiquitylation of EGFR after stimulation with heparin-binding EGF or amphiregulin and alters the rate of recruitment of the activated receptor to EEA1-positive endosomes. The suppressive effect of CD82 is dependent on the heparin-binding domain of the ligand. Deletion of the C-terminal cytoplasmic domain of CD82 (CD82ΔC mutant) inhibits endocytic trafficking of the tetraspanin and compromises its activity toward heparin-binding EGF-activated EGFR. Reduced ubiquitylation of EGFR is accompanied by PKC-dependent increase in serine phosphorylation of c-Cbl in cells expressing elevated levels of CD82. Furthermore, phosphorylation of threonine 654 (PKC phosphorylation site) in the juxtamembrane domain of the receptor is considerably increased in CD82-expressing cells. These results describe previously unsuspected links between tetraspanin proteins and ubiquitylation of their molecular partners (e.g., EGFR). Our data identify CD82 as a new regulator of c-Cbl, which discriminatively controls the activity of this E3 ubiquitin ligase toward heparin-binding ligand-EGFR pairs. Taken together, these observations provide an important new insight into the modulatory role of CD82 in endocytic trafficking of EGF receptor.
MeSH term(s)	Amphiregulin ; Cell Line ; EGF Family of Proteins ; Endosomes/genetics ; Endosomes/metabolism ; ErbB Receptors/genetics ; ErbB Receptors/metabolism ; Glycoproteins/genetics ; Glycoproteins/metabolism ; Humans ; Intercellular Signaling Peptides and Proteins/genetics ; Intercellular Signaling Peptides and Proteins/metabolism ; Kangai-1 Protein/genetics ; Kangai-1 Protein/metabolism ; Phosphorylation/physiology ; Protein Kinase C/genetics ; Protein Kinase C/metabolism ; Protein Structure, Tertiary ; Protein Transport/physiology ; Proto-Oncogene Proteins c-cbl/genetics ; Proto-Oncogene Proteins c-cbl/metabolism ; Ubiquitin-Protein Ligases/genetics ; Ubiquitin-Protein Ligases/metabolism ; Ubiquitination/physiology ; Vesicular Transport Proteins/genetics ; Vesicular Transport Proteins/metabolism
Chemical Substances	AREG protein, human ; Amphiregulin ; CD82 protein, human ; EGF Family of Proteins ; Glycoproteins ; Intercellular Signaling Peptides and Proteins ; Kangai-1 Protein ; Vesicular Transport Proteins ; early endosome antigen 1 ; Proto-Oncogene Proteins c-cbl (EC 2.3.2.27) ; Ubiquitin-Protein Ligases (EC 2.3.2.27) ; EGFR protein, human (EC 2.7.10.1) ; ErbB Receptors (EC 2.7.10.1) ; Protein Kinase C (EC 2.7.11.13) ; CBL protein, human (EC 6.3.2.-)
Language	English
Publishing date	2013-07-29
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2997-x
ISSN	1083-351X ; 0021-9258
ISSN (online)	1083-351X
ISSN	0021-9258
DOI	10.1074/jbc.M112.439380
Database	MEDical Literature Analysis and Retrieval System OnLINE

In stock of ZB MED Cologne/Königswinter

Uc I Zs.108: Show issues

Location:
Je nach Verfügbarkeit (siehe Angabe bei Bestand)
bis Jg. 2021: Bestellungen von Artikeln über das Online-Bestellformular
ab Jg. 2022: Lesesaal (EG)

Order via subito

Details ▾
- See ZB MED holdings
- Order with fees

To top

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

In stock of ZB MED Bonn / Germany

Order via subito

Inter-library loan at ZB MED

Full text online

More links

Kategorien

In stock of ZB MED Cologne/Königswinter

Order via subito

More links

Kategorien

Order via subito

Full text online

More links

Kategorien

Order via subito

Inter-library loan at ZB MED

More links

Kategorien

Order via subito

More links

Kategorien

Order via subito

More links

Kategorien

Order via subito

Full text online

More links

Kategorien

In stock of ZB MED Cologne/Königswinter

Order via subito

More links

Kategorien

In stock of ZB MED Cologne/Königswinter

Order via subito