LH/hCG and the Receptor: A Single Receptor for Two Ligands

Larvicides based on the bacteria Bacillus thuringiensis svar. israelensis (Bti) and Lysinibacillus sphaericus are effective and environmentally safe compounds for the control of dipteran insects of medical importance. They produce crystals that display specific and potent insecticidal activity against larvae. Bti crystals are composed of multiple protoxins: three from the three-domain Cry type family, which bind to different cell receptors in the midgut, and one cytolytic (Cyt1Aa) protoxin that can insert itself into the cell membrane and act as surrogate receptor of the Cry toxins. Together, those toxins display a complex mode of action that shows a low risk of resistance selection. L. sphaericus crystals contain one major binary toxin that display an outstanding persistence in field conditions, which is superior to Bti. However, the action of the Bin toxin based on its interaction with a single receptor is vulnerable for resistance selection in insects. In this review we present the most recent data on the mode of action and synergism of these toxins, resistance issues, and examples of their use worldwide. Data reported in recent years improved our understanding of the mechanism of action of these toxins, showed that their combined use can enhance their activity and counteract resistance, and reinforced their relevance for mosquito control programs in the future years.

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Identification of plant volatiles activating single receptor neurons in the pine weevil ( Hylobius abietis )

Journal of Comparative Physiology A ◽

10.1007/s003590050075 ◽

1997 ◽

Vol 180 (6) ◽

pp. 585-595 ◽

Cited By ~ 29

Author(s):

Atle Wibe ◽

Anna-Karin Borg-Karlson ◽

Torbjörn Norin ◽

Hanna Mustaparta

Keyword(s):

Plant Volatiles ◽

Hylobius Abietis ◽

Pine Weevil ◽

Single Receptor ◽

Receptor Neurons

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THE FREQUENCY OF ANTIGEN-SENSITIVE CELLS IN TISSUE TRANSPLANTATION

Journal of Experimental Medicine ◽

10.1084/jem.129.3.459 ◽

1969 ◽

Vol 129 (3) ◽

pp. 459-467 ◽

Cited By ~ 80

Author(s):

Norman W. Nisbet ◽

Morten Simonsen ◽

Marek Zaleski

Keyword(s):

Intravenous Injection ◽

Clonal Selection ◽

Tissue Transplantation ◽

Low Doses ◽

Receptor Specificity ◽

Adult Chicken ◽

Single Receptor ◽

Donor Cells ◽

Minimum Estimate ◽

Chicken Blood

Graft-vs.-host (GVH) reactions were performed in chicken embryos by intravenous injection of adult chicken blood dilutions, and the result was scored by weighing the spleens as well as by karyological identification of host and donor metaphases. From the frequency of detectable signs of GVH reaction when low doses of donor cells were injected into hosts containing one foreign allele of the B locus it is concluded that 1–2% must be a minimum estimate for the frequency of antigen-sensitive cells of a given specificity in this system. It is not found possible to reconcile the findings with the strictest form of clonal selection which postulates a single receptor specificity per clone of antigen-sensitive cells.

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Optimal ligand discrimination by asymmetric dimerization and turnover of interferon receptors

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2103939118 ◽

2021 ◽

Vol 118 (37) ◽

pp. e2103939118

Author(s):

Patrick Binder ◽

Nikolas D. Schnellbächer ◽

Thomas Höfer ◽

Nils B. Becker ◽

Ulrich S. Schwarz

Keyword(s):

Defense Mechanisms ◽

Antiviral Defense ◽

Discrimination Power ◽

Receptor System ◽

Information Theoretic ◽

Single Receptor ◽

Ligand Type ◽

Theoretic Problem ◽

Multicellular Organisms ◽

Receptor Turnover

In multicellular organisms, antiviral defense mechanisms evoke a reliable collective immune response despite the noisy nature of biochemical communication between tissue cells. A molecular hub of this response, the interferon I receptor (IFNAR), discriminates between ligand types by their affinity regardless of concentration. To understand how ligand type can be decoded robustly by a single receptor, we frame ligand discrimination as an information-theoretic problem and systematically compare the major classes of receptor architectures: allosteric, homodimerizing, and heterodimerizing. We demonstrate that asymmetric heterodimers achieve the best discrimination power over the entire physiological range of local ligand concentrations. This design enables sensing of ligand presence and type, and it buffers against moderate concentration fluctuations. In addition, receptor turnover, which drives the receptor system out of thermodynamic equilibrium, allows alignment of activation points for ligands of different affinities and thereby makes ligand discrimination practically independent of concentration. IFNAR exhibits this optimal architecture, and our findings thus suggest that this specialized receptor can robustly decode digital messages carried by its different ligands.

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Vitamin D

AJP Renal Physiology ◽

10.1152/ajprenal.00336.2004 ◽

2005 ◽

Vol 289 (1) ◽

pp. F8-F28 ◽

Cited By ~ 802

Author(s):

Adriana S. Dusso ◽

Alex J. Brown ◽

Eduardo Slatopolsky

Keyword(s):

Vitamin D ◽

Target Genes ◽

Endocrine System ◽

Target Cells ◽

Vitamin D Metabolism ◽

Diverse Range ◽

Hydroxyvitamin D ◽

Dihydroxyvitamin D ◽

Single Receptor ◽

Recent Developments

The vitamin D endocrine system plays an essential role in calcium homeostasis and bone metabolism, but research during the past two decades has revealed a diverse range of biological actions that include induction of cell differentiation, inhibition of cell growth, immunomodulation, and control of other hormonal systems. Vitamin D itself is a prohormone that is metabolically converted to the active metabolite, 1,25-dihydroxyvitamin D [1,25(OH)2D]. This vitamin D hormone activates its cellular receptor (vitamin D receptor or VDR), which alters the transcription rates of target genes responsible for the biological responses. This review focuses on several recent developments that extend our understanding of the complexities of vitamin D metabolism and actions: the final step in the activation of vitamin D, conversion of 25-hydroxyvitamin D to 1,25(OH)2D in renal proximal tubules, is now known to involve facilitated uptake and intracellular delivery of the precursor to 1α-hydroxylase. Emerging evidence using mice lacking the VDR and/or 1α-hydroxylase indicates both 1,25(OH)2D3-dependent and -independent actions of the VDR as well as VDR-dependent and -independent actions of 1,25(OH)2D3. Thus the vitamin D system may involve more than a single receptor and ligand. The presence of 1α-hydroxylase in many target cells indicates autocrine/paracrine functions for 1,25(OH)2D3in the control of cell proliferation and differentiation. This local production of 1,25(OH)2D3is dependent on circulating precursor levels, providing a potential explanation for the association of vitamin D deficiency with various cancers and autoimmune diseases.

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Identification and characterization of RNA aptamers: A long aptamer blocks the AMPA receptor and a short aptamer blocks both AMPA and kainate receptors

Journal of Biological Chemistry ◽

10.1074/jbc.m116.774752 ◽

2017 ◽

Vol 292 (18) ◽

pp. 7338-7347 ◽

Cited By ~ 6

Author(s):

William J. Jaremko ◽

Zhen Huang ◽

Wei Wen ◽

Andrew Wu ◽

Nicholas Karl ◽

...

Keyword(s):

Ampa Receptor ◽

Neurological Diseases ◽

Rna Aptamers ◽

Kainate Receptors ◽

Single Receptor ◽

Cell Recording ◽

Exponential Enrichment ◽

High Degree

AMPA and kainate receptors, along with NMDA receptors, represent different subtypes of glutamate ion channels. AMPA and kainate receptors share a high degree of sequence and structural similarities, and excessive activity of these receptors has been implicated in neurological diseases such as epilepsy. Therefore, blocking detrimental activity of both receptor types could be therapeutically beneficial. Here, we report the use of an in vitro evolution approach involving systematic evolution of ligands by exponential enrichment with a single AMPA receptor target (i.e. GluA1/2R) to isolate RNA aptamers that can potentially inhibit both AMPA and kainate receptors. A full-length or 101-nucleotide (nt) aptamer selectively inhibited GluA1/2R with a KI of ∼5 μm, along with GluA1 and GluA2 AMPA receptor subunits. Of note, its shorter version (55 nt) inhibited both AMPA and kainate receptors. In particular, this shorter aptamer blocked equally potently the activity of both the GluK1 and GluK2 kainate receptors. Using homologous binding and whole-cell recording assays, we found that an RNA aptamer most likely binds to the receptor's regulatory site and inhibits it noncompetitively. Our results suggest the potential of using a single receptor target to develop RNA aptamers with dual activity for effectively blocking both AMPA and kainate receptors.

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Probable mechanoreceptor structures of osphradia in marine Caenogastropoda

Ruthenica, Russian Malacological Journal ◽

10.35885/ruthenica.2021.30(1).4 ◽

2020 ◽

Vol 30 (1) ◽

pp. 33-39

Author(s):

N. N. Kamardin

Keyword(s):

Electron Microscopy ◽

Apical Surface ◽

Supporting Cells ◽

Receptor Cells ◽

Single Receptor

TEM and SEM electron microscopy have been used to study osphradia in 6 species of marine Caenogastropoda. The ultrastructural features of mechanoreceptor cells that perform the Littorina osmoreception function in osphradium organs are presented. Mechanoreception is based on a possible change in the volume of cisterns of microvilli of supporting cells, which can be transmitted by the cilia of nearby mechanoreceptor cells. These cells obviously, have mechanosensory channels on the apical surface. It has been first discovered in predatory molluscs actively searching for food, that single receptor cells with a mobile sensilla consisting of several cilium were joined together. They are located along the groove zone and follow the direction and force of the movement of water along the osphradium petals.

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