scholarly journals Somatostatin-Induced Regulation of SST2A Receptor Expression and Cell Surface Availability in Central Neurons: Role of Receptor Internalization

2000 ◽  
Vol 20 (16) ◽  
pp. 5932-5939 ◽  
Author(s):  
Hélène Boudin ◽  
Philippe Sarret ◽  
Jean Mazella ◽  
Agnes Schonbrunn ◽  
Alain Beaudet
Keyword(s):  
Cell Surface ◽  
Receptor Expression ◽  
Receptor Internalization ◽  
Central Neurons

Assembly, organization and regulation of cell-surface receptors by lectin–glycan complexes

2015 ◽  
Vol 469 (1) ◽  
pp. 1-16 ◽  
Author(s):  
María T. Elola ◽  
Ada G. Blidner ◽  
Fátima Ferragut ◽  
Candelaria Bracalente ◽  
Gabriel A. Rabinovich
Keyword(s):  
Cell Surface ◽  
Protein Interactions ◽  
Consensus Sequence ◽  
Hierarchical Organization ◽  
Receptor Expression ◽  
Receptor Internalization ◽  
Local Concentration ◽  
Surface Receptors ◽  
Extracellular Milieu ◽  
Galectin 3

Galectins are a family of β-galactoside-binding lectins carrying at least one consensus sequence in the carbohydrate-recognition domain. Properties of glycosylated ligands, such as N- and O-glycan branching, LacNAc (N-acetyl-lactosamine) content and the balance of α2,3- and α2,6-linked sialic acid dramatically influence galectin binding to a preferential set of counter-receptors. The presentation of specific glycans in galectin-binding partners is also critical, as proper orientation and clustering of oligosaccharide ligands on multiple carbohydrate side chains increase the binding avidity of galectins for particular glycosylated receptors. When galectins are released from the cells, they typically concentrate on the cell surface and the local matrix, raising their local concentration. Thus galectins can form their own multimers in the extracellular milieu, which in turn cross-link glycoconjugates on the cell surface generating galectin–glycan complexes that modulate intracellular signalling pathways, thus regulating cellular processes such as apoptosis, proliferation, migration and angiogenesis. Subtle changes in receptor expression, rates of protein synthesis, activities of Golgi enzymes, metabolite concentrations supporting glycan biosynthesis, density of glycans, strength of protein–protein interactions at the plasma membrane and stoichiometry may modify galectin–glycan complexes. Although galectins are key contributors to the formation of these extended glycan complexes leading to promotion of receptor segregation/clustering, and inhibition of receptor internalization by surface retention, when these complexes are disrupted, some galectins, particularly galectin-3 and -4, showed the ability to drive clathrin-independent mechanisms of endocytosis. In the present review, we summarize the data available on the assembly, hierarchical organization and regulation of conspicuous galectin–glycan complexes, and their implications in health and disease.

scholarly journals Dual role of ERK5 in the regulation of T cell receptor expression at the T cell surface

2015 ◽  
Vol 99 (1) ◽  
pp. 143-152 ◽  
Author(s):  
Xavier Rovira-Clavé ◽  
Maria Angulo-Ibáñez ◽  
Cathy Tournier ◽  
Manuel Reina ◽  
Enric Espel
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Dual Role ◽  
Receptor Expression

scholarly journals Interleukin-3 down-regulates its own receptor

Blood ◽  
1989 ◽  
Vol 73 (5) ◽  
pp. 1180-1187
Author(s):  
SC Murthy ◽  
PH Sorensen ◽  
AL Mui ◽  
G Krystal
Keyword(s):  
Cell Surface ◽  
Calf Serum ◽  
High Density ◽  
Receptor Expression ◽  
Receptor Internalization ◽  
Cell Surface Receptor ◽  
Cell Populations ◽  
Low Density ◽  
Interleukin 3 ◽  
Receptor Number

To gain insight into the mechanisms involved in regulating murine interleukin-3 (mIL-3) receptor expression, we have examined the effects of mIL-3 and murine granulocyte-macrophage colony-stimulating factor (mGM-CSF) on mIL-3 receptor internalization and re-expression and studied the relationship between mIL-3 cell surface receptor density and growth factor sensitivity. As a source of cells for our studies, we used a B6SUtA clone, B6SUtA1, which grows equally well in mIL-3 or mGM- CSF when supplemented with 20% fetal calf serum (FCS) in RPMI 1640. Intracellular processing studies carried out in the presence and absence of methylamine suggested that mIL-3 is cleaved at two specific sites before its complete digestion within lysosomes. However, unlike its ligand, cycloheximide studies indicated that internalized mIL-3 receptors are recycled to the cell surface. When B6SUtA1 cells were continuously passaged in mIL-3, cell populations allowed to exhaust the mIL-3 in the medium (high density cells) expressed more than ten times (ie, approximately 100,000/cell) the mIL-3 receptor number of those growing exponentially at low cell concentrations (low density cells). Since the high density cells were no larger than the low density cells, the marked increase in mIL-3 receptor number per cell reflects a true up-regulation of receptor expression. A kinetic analysis of this up- regulation revealed that it begins within one hour of mIL-3 exhaustion. Moreover, proliferation assays with these two cell populations, using 3H-thymidine incorporation, suggested that the high density cells were 30-fold more responsive to mIL-3. However, when B6SUtA1 cells were passaged in mGM-CSF, there was no difference in mIL-3 receptor number between high density and low density cells (ie, approximately 100,000/cell). Identical studies carried out with another mIL-3 dependent cell line, 32D C3, demonstrated that this phenomenon was not unique to B6SUtA1 cells.

scholarly journals Interleukin-3 down-regulates its own receptor

Blood ◽  
1989 ◽  
Vol 73 (5) ◽  
pp. 1180-1187 ◽  
Author(s):  
SC Murthy ◽  
PH Sorensen ◽  
AL Mui ◽  
G Krystal
Keyword(s):  
Cell Surface ◽  
Calf Serum ◽  
High Density ◽  
Receptor Expression ◽  
Receptor Internalization ◽  
Cell Surface Receptor ◽  
Cell Populations ◽  
Low Density ◽  
Interleukin 3 ◽  
Receptor Number

Abstract To gain insight into the mechanisms involved in regulating murine interleukin-3 (mIL-3) receptor expression, we have examined the effects of mIL-3 and murine granulocyte-macrophage colony-stimulating factor (mGM-CSF) on mIL-3 receptor internalization and re-expression and studied the relationship between mIL-3 cell surface receptor density and growth factor sensitivity. As a source of cells for our studies, we used a B6SUtA clone, B6SUtA1, which grows equally well in mIL-3 or mGM- CSF when supplemented with 20% fetal calf serum (FCS) in RPMI 1640. Intracellular processing studies carried out in the presence and absence of methylamine suggested that mIL-3 is cleaved at two specific sites before its complete digestion within lysosomes. However, unlike its ligand, cycloheximide studies indicated that internalized mIL-3 receptors are recycled to the cell surface. When B6SUtA1 cells were continuously passaged in mIL-3, cell populations allowed to exhaust the mIL-3 in the medium (high density cells) expressed more than ten times (ie, approximately 100,000/cell) the mIL-3 receptor number of those growing exponentially at low cell concentrations (low density cells). Since the high density cells were no larger than the low density cells, the marked increase in mIL-3 receptor number per cell reflects a true up-regulation of receptor expression. A kinetic analysis of this up- regulation revealed that it begins within one hour of mIL-3 exhaustion. Moreover, proliferation assays with these two cell populations, using 3H-thymidine incorporation, suggested that the high density cells were 30-fold more responsive to mIL-3. However, when B6SUtA1 cells were passaged in mGM-CSF, there was no difference in mIL-3 receptor number between high density and low density cells (ie, approximately 100,000/cell). Identical studies carried out with another mIL-3 dependent cell line, 32D C3, demonstrated that this phenomenon was not unique to B6SUtA1 cells.

Receptor externalization determines sustained contractile responses to endothelin-1 in the rat aorta

1993 ◽  
Vol 264 (3) ◽  
pp. C687-C693 ◽  
Author(s):  
R. Marsault ◽  
E. Feolde ◽  
C. Frelin
Keyword(s):  
Angiotensin Ii ◽  
Cell Surface ◽  
Dissociation Constant ◽  
Rat Aorta ◽  
Receptor Internalization ◽  
Contractile Responses ◽  
Endothelin 1 ◽  
Receptor Sites

The role of receptor internalization and recycling in the vasoconstrictor action of endothelin-1 (ET-1) is investigated using a combination of biochemical and physiological experiments. The binding of 125I-ET-1 to cultured aortic myocytes is first defined. Binding is rapidly followed by an internalization of the peptide. Part of the receptor sites then slowly reappears at the cell surface via a cycloheximide-insensitive mechanism. Evidence that externalizing receptors are functional and can trigger contractions is presented. Finally, the actions of cyclo[D-Trp-D-Asp-Pro-D-Val-Leu] (BQ-123), an antagonist of ETA receptors, are investigated. BQ-123 prevents 125I-ET-1 binding to aortic myocytes (dissociation constant, 10 nM). It prevents the constricting action of ET-1 but not that of angiotensin II. BQ-123 also relaxes almost completely aortic strips that have been precontracted by ET-1 irrespective of the time of its addition. It is concluded that a recycling of internalized ET-1 receptors occurs in ET-1-treated aortic myocytes. This process amplifies the action of the peptide and is probably responsible for the unique contractile action of ET-1.

scholarly journals The Glucagon-like Peptide-2 Receptor C Terminus Modulates β-Arrestin-2 Association but Is Dispensable for Ligand-induced Desensitization, Endocytosis, and G-protein-dependent Effector Activation

2005 ◽  
Vol 280 (23) ◽  
pp. 22124-22134 ◽  
Author(s):  
Jennifer L. Estall ◽  
Jacqueline A. Koehler ◽  
Bernardo Yusta ◽  
Daniel J. Drucker
Keyword(s):  
Cell Surface ◽  
G Protein ◽  
Receptor Expression ◽  
Receptor Internalization ◽  
Cell Surface Receptor ◽  
Receptor Desensitization ◽  
C Terminus ◽  
The Family ◽  
Surface Receptor ◽  
Glucagon Like Peptide

Classic models of receptor desensitization and internalization have been largely based on the behavior of Family A G-protein-coupled receptors (GPCRs). The glucagon-like peptide-2 receptor (GLP-2R) is a member of the Family B glucagon-secretin GPCR family, which exhibit significant sequence and structural differences from the Family A receptors in their intracellular and extracellular domains. To identify structural motifs that regulate GLP-2R signaling and cell surface receptor expression, we analyzed the functional properties of a series of mutant GLP-2Rs. The majority of the C-terminal receptor tail was dispensable for GLP-2-induced cAMP accumulation, ERK1/2 activation, and endocytosis in transfected cells. However, progressive truncation of the C terminus reduced cell surface receptor expression, altered agonist-induced GLP-2R trafficking, and abrogated protein kinase A-mediated heterologous receptor desensitization. Elimination of the distal 21 amino acids of the receptor was sufficient to promote constitutive receptor internalization and prevent agonist-induced recruitment of β-arrestin-2. Site-directed mutagenesis identified specific amino acid residues within the distal GLP-2R C terminus that mediate the stable association with β-arrestin-2. Surprisingly, although the truncated mutant receptors failed to interact with β-arrestin-2, they underwent homologous desensitization and subsequent resensitization with kinetics similar to that observed with the wild-type GLP-2R. Our data suggest that, although the GLP-2R C terminus is not required for coupling to cellular machinery regulating signaling or desensitization, it may serve as a sorting signal for intracellular trafficking. Taken together with the previously demonstrated clathrin and dynamin-independent, lipid-raft-dependent pathways for internalization, our data suggest that GLP-2 receptor signaling has evolved unique structural and functional mechanisms for control of receptor trafficking, desensitization, and resensitization.

Role of the 807 C/T Polymorphism of the α2 Gene in Platelet GP Ia Collagen Receptor Expression and Function

1999 ◽  
Vol 81 (06) ◽  
pp. 951-956 ◽  
Author(s):  
J. Corral ◽  
R. González-Conejero ◽  
J. Rivera ◽  
F. Ortuño ◽  
P. Aparicio ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Cell Types ◽  
Receptor Expression ◽  
Case Control Studies ◽  
Platelet Surface ◽  
Vitro Analysis ◽  
And Function ◽  
In Vitro Analysis

SummaryThe variability of the platelet GP Ia/IIa density has been associated with the 807 C/T polymorphism (Phe 224) of the GP Ia gene in American Caucasian population. We have investigated the genotype and allelic frequencies of this polymorphism in Spanish Caucasians. The T allele was found in 35% of the 284 blood donors analyzed. We confirmed in 159 healthy subjects a significant association between the 807 C/T polymorphism and the platelet GP Ia density. The T allele correlated with high number of GP Ia molecules on platelet surface. In addition, we observed a similar association of this polymorphism with the expression of this protein in other blood cell types. The platelet responsiveness to collagen was determined by “in vitro” analysis of the platelet activation and aggregation response. We found no significant differences in these functional platelet parameters according to the 807 C/T genotype. Finally, results from 3 case/control studies involving 302 consecutive patients (101 with coronary heart disease, 104 with cerebrovascular disease and 97 with deep venous thrombosis) determined that the 807 C/T polymorphism of the GP Ia gene does not represent a risk factor for arterial or venous thrombosis.

The Role of the Interaction between Fe(III) and Cell Surface in the Accumulation of 67Ga by Tumor Cells

1991 ◽  
Vol 30 (06) ◽  
pp. 290-293 ◽  
Author(s):  
P. Maleki ◽  
A. Martinezi ◽  
M. C. Crone-Escanye ◽  
J. Robert ◽  
L. J. Anghileri
Keyword(s):  
Cell Surface ◽  
Tumor Cells ◽  
Ionic Composition ◽  
Iron Complex ◽  
Iron Binding ◽  
Complex Time ◽  
Interaction Product ◽  
Thermodynamic Constant ◽  
Number Of Cells

The study of the interaction between complexed iron and tumor cells in the presence of 67Ga-citrate indicates that a phenomenon of iron-binding related to the thermodynamic constant of stability of the iron complex, and a hydrolysis (or anion penetration) of the interaction product determine the uptake of 67Ga. The effects of various parameters such as ionic composition of the medium, nature of the iron complex, time of incubation and number of cells are discussed.

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