A protective receptor pool

2014 ◽  
Vol 15 (7) ◽  
pp. 426-427
Author(s):  
Leonie Welberg
Keyword(s):  
Receptor Pool

scholarly journals α4β1Integrin-dependent Cell Adhesion Is Regulated by a Low Affinity Receptor Pool That Is Conformationally Responsive to Ligand

1995 ◽  
Vol 270 (48) ◽  
pp. 28740-28750 ◽  
Author(s):  
Ted A. Yednock ◽  
Catherine Cannon ◽  
Christopher Vandevert ◽  
Erich G. Goldbach ◽  
Gray Shaw ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Dependent Cell ◽  
Affinity Receptor ◽  
Receptor Pool

scholarly journals Regulation of receptors and digestive activity toward synthesized formyl-chemotactic peptide in human polymorphonuclear leukocytes

Blood ◽  
1985 ◽  
Vol 66 (1) ◽  
pp. 106-114
Author(s):  
H Nunoi ◽  
F Endo ◽  
S Chikazawa ◽  
I Matsuda
Keyword(s):  
Cord Blood ◽  
Receptor Binding ◽  
Polymorphonuclear Leukocytes ◽  
Binding Activity ◽  
Intracellular Receptor ◽  
Terminal Amino ◽  
Carboxyl Terminal ◽  
Human Polymorphonuclear Leukocytes ◽  
Receptor Pool ◽  
Digestive Activity

A receptor binding and digestive activity of human polymorphonuclear leukocytes (PMNs) toward formyl-methionyl-leucyl-[3H]phenylalanine (3H- FMLP) was examined with the following results: Up- and down-regulation and recovery of 3H-FMLP binding activity were demonstrated. Both intact PMN and a lysate prepared from them cleaved the carboxyl terminal amino acid (phenylalanine) of 3H-FMLP. The digestive activity decreased as the receptor binding was inhibited by n-ethylmaleimide and 4- chloromercuribenzoate. Little digestive activity was found in the supernatant from PMN stimulated by FMLP. The released phenylalanine was found in the pellet and supernatant of PMNs. Digestive activity with cathepsin A-like characteristics was found in the lysate of PMN. These observations suggest that FMLP is internalized in lysosomes in a receptor-mediated manner and cleaved by the cathepsin A-like enzyme, the free phenylalanine is released extracellularly, and a part of the dissociated receptors with FMLP may return to the surface or to an intracellular receptor pool. Another finding was that the digestive activity of the lysate of cord blood granulocytes was decreased compared with that of adult blood granulocytes. This decrease may explain in part the impaired chemotaxis of cord blood granulocytes.

scholarly journals Competition for synaptic building blocks shapes synaptic plasticity

2017 ◽  
Author(s):  
Jochen Triesch ◽  
Anh Duong Vo ◽  
Anne-Sophie Hafner
Keyword(s):  
Mathematical Model ◽  
Synaptic Plasticity ◽  
Learning And Memory ◽  
Time Scales ◽  
Building Blocks ◽  
Neurotransmitter Receptors ◽  
Rapid Exchange ◽  
Heterosynaptic Plasticity ◽  
Spontaneous Fluctuations ◽  
Receptor Pool

AbstractChanges in the efficacies of synapses are thought to be the neurobiological basis of learning and memory. The efficacy of a synapse depends on its current number of neurotransmitter receptors. Recent experiments have shown that these receptors are highly dynamic, moving back and forth between synapses on time scales of seconds and minutes. This suggests spontaneous fluctuations in synaptic efficacies and a competition of nearby synapses for available receptors. Here we propose a mathematical model of this competition of synapses for neurotransmitter receptors from a local dendritic pool. Using minimal assumptions, the model produces a fast multiplicative scaling behavior of synapses. Furthermore, the model explains a transient form of heterosynaptic plasticity and predicts that its amount is inversely related to the size of the local receptor pool. Overall, our model reveals logistical tradeoffs during the induction of synaptic plasticity due to the rapid exchange of neurotransmitter receptors between synapses.

Down-regulation of Drosophila Egf-r mRNA levels following hyperactivated receptor signaling

Development ◽  
1994 ◽  
Vol 120 (9) ◽  
pp. 2593-2600 ◽  
Author(s):  
M.A. Sturtevant ◽  
J.W. O'Neill ◽  
E. Bier
Keyword(s):  
Mrna Stability ◽  
Egf Receptor ◽  
Receptor Internalization ◽  
Ras Signaling ◽  
Mrna Levels ◽  
Down Regulation ◽  
Feedback Mechanisms ◽  
Receptor Complexes ◽  
Surface Receptor ◽  
Receptor Pool

Internalization of ligand-receptor complexes is a well-documented mechanism for limiting the duration and magnitude of a signaling event. In the case of the EGF-Receptor (EGF-R), exposure to EGF or TGF-alpha results in internalization of up to 95% of the surface receptor pool within 5 minutes of exposure to ligand. In this report, we show that levels of Drosophila Egf-r mRNA are strongly down-regulated in epidermal cells likely to have recently undergone high levels of EGF-R signaling. The cells in which Egf-r mRNA levels are down-regulated express the rhomboid gene, which is thought to locally amplify EGF-R signaling. Widespread Egf-r mRNA down-regulation can be induced by ubiquitous expression of rhomboid or by eliminating the Gap1 gene. These results suggest that cells engaged in intense EGF-R/RAS signaling limit the duration of the signal through a combination of short-acting negative feedback mechanisms such as receptor internalization followed by a longer lasting reduction in receptor transcript levels. Control of Egf-r mRNA levels by altering transcription or mRNA stability is a new tier of regulation to be considered in analysis of EGF-R signaling during development.

scholarly journals Extranuclear estrogen receptor's roles in physiology: lessons from mouse models

2014 ◽  
Vol 307 (2) ◽  
pp. E133-E140 ◽  
Author(s):  
Ellis R. Levin
Keyword(s):  
Mouse Models ◽  
Sex Steroids ◽  
Steroid Receptors ◽  
Sex Steroid ◽  
Normal Cells ◽  
Receptor Localization ◽  
Selective Agonists ◽  
And Function ◽  
Receptor Pool ◽  
Made In

Steroid receptors exist and function in multiple compartments of cells in most organs. Although the functions and nature of some of these receptors is being defined, important aspects of receptor localization and signaling to physiology and pathophysiology have been identified. In particular, extranuclear sex steroid receptors have been found in many normal cells and in epithelial tumors, where they enact signal transduction that impacts both nongenomic and genomic functions. Here, I focus on the progress made in understanding the roles of extranuclear estrogen receptors (ER) in physiology and pathophysiology. Extranuclear ER serve as a model to selectively intervene with novel receptor reagents to prevent or limit disease progression. Recent novel mouse models and membrane ER-selective agonists also provide a better understanding of receptor pool cross-talk that results in the overall integrative actions of sex steroids.

scholarly journals Regulation of receptors and digestive activity toward synthesized formyl-chemotactic peptide in human polymorphonuclear leukocytes

Blood ◽  
1985 ◽  
Vol 66 (1) ◽  
pp. 106-114 ◽  
Author(s):  
H Nunoi ◽  
F Endo ◽  
S Chikazawa ◽  
I Matsuda
Keyword(s):  
Cord Blood ◽  
Receptor Binding ◽  
Polymorphonuclear Leukocytes ◽  
Binding Activity ◽  
Intracellular Receptor ◽  
Terminal Amino ◽  
Carboxyl Terminal ◽  
Human Polymorphonuclear Leukocytes ◽  
Receptor Pool ◽  
Digestive Activity

Abstract A receptor binding and digestive activity of human polymorphonuclear leukocytes (PMNs) toward formyl-methionyl-leucyl-[3H]phenylalanine (3H- FMLP) was examined with the following results: Up- and down-regulation and recovery of 3H-FMLP binding activity were demonstrated. Both intact PMN and a lysate prepared from them cleaved the carboxyl terminal amino acid (phenylalanine) of 3H-FMLP. The digestive activity decreased as the receptor binding was inhibited by n-ethylmaleimide and 4- chloromercuribenzoate. Little digestive activity was found in the supernatant from PMN stimulated by FMLP. The released phenylalanine was found in the pellet and supernatant of PMNs. Digestive activity with cathepsin A-like characteristics was found in the lysate of PMN. These observations suggest that FMLP is internalized in lysosomes in a receptor-mediated manner and cleaved by the cathepsin A-like enzyme, the free phenylalanine is released extracellularly, and a part of the dissociated receptors with FMLP may return to the surface or to an intracellular receptor pool. Another finding was that the digestive activity of the lysate of cord blood granulocytes was decreased compared with that of adult blood granulocytes. This decrease may explain in part the impaired chemotaxis of cord blood granulocytes.

Arginine vasopressin metabolism in dogs. II. Modeling and system analysis.

1978 ◽  
Vol 235 (6) ◽  
pp. E598
Author(s):  
K C Wilson ◽  
R E Weitzman ◽  
D A Fisher
Keyword(s):  
Arginine Vasopressin ◽  
Hormone Receptors ◽  
System Analysis ◽  
System Modeling ◽  
Urine Excretion ◽  
Modeling And Analysis ◽  
Unique Model ◽  
Pool Model ◽  
Receptor Pool ◽  
Vascular Compartment

System modeling and analysis methods were applied to interpret data regarding arginine vasopressin (AVP) metabolism in dogs. Based on this analysis a new nonlinear 3-pool model of AVP distribution and disposal was proposed and quantified; the model pools included the plasma, a receptor pool, and an extravascular nonreceptor pool. The receptor pool mediated a portion of the rapid flux of hormone between the plasma and the extravascular pool. Mathematical analysis indicated that the plasma AVP impulse response (bolus) data would be insufficient to uniquely estimate all the model constants, but additional plasma impulse data using 125I-labeled AVP, which does not bind to physiologic hormone receptors, would allow unique model quantification. Other required measurements were the urinary excretion of intact hormone, and plasma AVP degradation. The model was successfully fitted to the data from 10 dogs. The results suggest that, in the normal dogs studied, plasma contained 25% of the total AVP, 19% was bound to receptors, and the remaining 56% was in the extravascular pool. Eighty percent of the flux of AVP from the vascular compartment was mediated by the receptor pool; 98% of AVP degradation occurred in the extravascular pool; and urine excretion and plasma degradation made up the remainder.

scholarly journals Evidence that the thyrotropin-releasing hormone receptor and its ligand are recycled dissociated from each other

1995 ◽  
Vol 306 (1) ◽  
pp. 107-113 ◽  
Author(s):  
C P Petrou ◽  
A H Tashjian
Keyword(s):  
Cell Surface ◽  
Hormone Receptor ◽  
Thyrotropin Releasing Hormone ◽  
Cell Surface Receptor ◽  
Acidic Ph ◽  
Receptor Recycling ◽  
Bafilomycin A1 ◽  
Receptor Ligand ◽  
Surface Receptor ◽  
Receptor Pool

We have examined the trafficking of the thyrotropin-releasing hormone receptor (TRHR) and its ligand, after TRHR-TRH internalization in rat pituitary GH4C1 cells. After rapid ligand-induced receptor sequestration, the cell surface receptor pool was replenished. Replenishment was insensitive to inhibition of protein synthesis and was dependent on the duration of internalization; therefore, the replenished receptors were not newly synthesized but recycled. The total amount of recycled receptors decreased with increasing internalization time, resulting in only partial replenishment of the cell-surface receptor pool after prolonged incubation with ligand. Thus, in addition to a receptor recycling pathway, a non-cycling route exists for TRHR sorting; this route became dominant with increasing internalization periods. TRHR entry into these pathways was not determined by the affinity of the receptor-ligand interaction, because the extent of receptor recycling was similar after TRH- and methyl-TRH (MeTRH)-induced internalization. Unlike results with the TRHR, the TRH recycling pool was not depleted by the noncycling pathway. After multiple rounds of [3H]MeTRH internalization, the amount of cell-associated radioactivity increased with increasing internalization time due to accumulation of the ligand or its metabolites in a non-cycling pathway, but the absolute amount of recycled ligand remained constant after short or long internalization times. The difference in the proportion of TRHR and MeTRH that were diverted into a noncycling pathway indicated intracellular dissociation of the internalized TRHR-TRH complex. Dissociation of the internalized TRHR-TRH complex was dependent on the acidic pH in an intracellular compartment. Although extracellular acidic pH did not enhance cell-surface receptor-ligand (RL) dissociation, bafilomycin A1 inhibited both receptor and ligand recycling. We conclude that the TRHR-TRH system is unique among recycling receptors because, after RL sequestration, the TRHR-TRH complex becomes dissociated intracellularly via a bafilomycin A1-sensitive, acidic pH-dependent mechanism, and both the unoccupied TRHR and TRH recycle disassociated from each other.

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