Comparative studies of insulin binding to receptor from adipocytes, hepatocytes, monocytes and erythrocytes from the pig

1988 ◽  
Vol 118 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Elisabeth Hjøllund ◽  
Bjørn Richelsen ◽  
Oluf Pedersen
Keyword(s):  
Steady State ◽  
Receptor Binding ◽  
Specific Binding ◽  
Insulin Binding ◽  
Cell Types ◽  
Target Cells ◽  
Suitable Model ◽  
The Individual ◽  
Different Cell Types ◽  
Specific Insulin

Abstract. We have described the receptor binding of A 14-labelled [125I]insulin to viable adipocytes, hepatocytes, monocytes and erythrocytes from the pig. For all cell types the binding was of high affinity, specific for insulin, the non-specific binding low and degradation of insulin in the medium was minimal. At 24°C, steady state insulin binding was achieved in all four cell types. At 37°C, steady state insulin binding could be measured to adipocytes and hepatocytes. Specific insulin binding levels and receptor affinity for blood and fat cells from the pig are comparable to that in human cells, whereas differences, especially according to affinity, exist between pig and rat cell insulin receptor binding. It is therefore concluded that the pig is a more suitable model for studies of insulin binding in man than rodents. Finally, no correlations between the individual binding levels to the different cell types were observed. Hence, measurement of insulin binding to the easier available blood cells cannot replace studies of insulin binding to target cells of insulin.

Role of Transcriptional Read-Through in PRE Activity in Drosophila melanogaster

Acta Naturae ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 79-86 ◽  
Author(s):  
P. V. Elizar’ev ◽  
D. V. Lomaev ◽  
D. A. Chetverina ◽  
P. G. Georgiev ◽  
M. M. Erokhin
Keyword(s):  
Dna Sequences ◽  
Cell Types ◽  
Transcription Terminator ◽  
Response Elements ◽  
Polycomb Response Elements ◽  
The Individual ◽  
Multicellular Organisms ◽  
Different Cell Types ◽  
Main Factor

Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation. In this study, we analyzed the influence of transcriptional read-through on PRE activity switch mediated by the yeast activator GAL4. We show that a transcription terminator inserted between the promoter and PRE doesnt prevent switching of PRE activity from repression to activation. We demonstrate that, independently of PRE orientation, high levels of transcription fail to dislodge PcG/TrxG proteins from PRE in the absence of a terminator. Thus, transcription is not the main factor required for PRE activity switch.

An Overview of the Latest Applications of Platelet-Derived Microparticles and Nanoparticles in Medical Technology 2010-2020

2021 ◽  
Vol 21 ◽  
Author(s):  
Tahereh Zadeh Mehrizi
Keyword(s):  
Drug Delivery ◽  
Cell Types ◽  
Current Status ◽  
Target Cells ◽  
Interesting Point ◽  
Large Size ◽  
Review Study ◽  
Cellular Pathways ◽  
Different Cell Types

: Today, Platelets and platelet-derived nanoparticles and microparticles have found many applications in nanomedical technology. The results of our review study show that no article has been published in this field to review the current status of applications of these platelet derivatives so far. Therefore, in present study, our goal is to compare the applications of platelet derivatives and review their latest status between 2010 and 2020 to present the latest findings to researchers. A very interesting point about the role of platelet derivatives is the presence of molecules on their surface which makes them capable of hiding from the immune system, reaching different target cells, and specifically attaching to different cell types. According to the results of this study, most of their applications include drug delivery, diagnosis of various diseases, and tissue engineering. However, their application in drug delivery is limited due to heterogeneity, large size, and the possibility of interference with cellular pathways in microparticles derived from other cells. On the other hand, platelet nanoparticles are more controllable and have been widely used for drug delivery in treatment of cancer, atherosclerosis, thrombosis, infectious diseases, repair of damaged tissue, and photothermal therapy. The results of this study show that platelet nanoparticles are more controllable than platelet microparticles and have a higher potential for use in medicine.

Specific binding of [3H]oxytocin in the female rat brain

1983 ◽  
Vol 61 (9) ◽  
pp. 989-995 ◽  
Author(s):  
B. M. Ferrier ◽  
S.A. McClorry ◽  
A. W. Cochrane
Keyword(s):  
Plasma Membrane ◽  
Limbic System ◽  
Microsomal Fraction ◽  
Specific Binding ◽  
Cell Types ◽  
Time Dependent ◽  
Female Rat ◽  
Ph Optimum ◽  
Rat Tissue ◽  
Different Cell Types

Because of demonstrated effects of oxytocin on some limbic system mediated behaviours, the specific binding of [3H]oxytocin to a plasma membrane containing fraction of rat limbic tissue has been studied. The binding of the microsomal fraction of estrogenized, female rat tissue was time dependent and saturable, with a Bmax of 2.5 × 10−l3 moles per milligram of protein and an apparent KD of 3.53 × 10−8 M, and appeared to show positive cooperativity. The pH optimum of the binding was 6.0, close to the pH optimum for oxytocin – neurophysin binding; however, other results show the two types of binding to be different. The microsomal fraction did not appreciably degrade oxytocin under the conditions used for [3H]oxytocin binding. The distribution in limbic tissue of oxytocin-degrading activity and of individual enzymes capable of degrading oxytocin has been examined and an interplay of enzymes concentrated in different cell types is proposed.

A quantitative study of the chorioallantoic membrane reaction in the chick embryo

1966 ◽  
Vol 163 (993) ◽  
pp. 555-563 ◽  
Keyword(s):  
Chick Embryo ◽  
Chorioallantoic Membrane ◽  
Cell Types ◽  
Variable Number ◽  
Logarithmic Scale ◽  
Focal Lesions ◽  
Specific Test ◽  
The Individual ◽  
Response Line ◽  
Different Cell Types

When a suspension of living adult chick leucocytes is placed in contact with the chorioallantoic membrane (CAM) of a developing chick embryo, a variable number of white focal lesions appear a few days later. The number of foci is positively correlated with the number of cells in the inoculum. The phenomenon is known to be an expression of an immunological reaction of the grafted cells against the host. F. M. Burnet and his colleagues have suggested that each focus results from the immunological activity of one and only one cell. If this presumption were confirmed the CAM system would gain in usefulness, in particular for the isolation of clones of immunologically competent cells. In the present work this ‘single-hit’ hypothesis has been subjected to a specific test of its biometrical consequences. On the single-hit model the response should be proportional to the dose. Equivalently, on the logarithmic scale of measurement adopted in these experiments, the fitted dose-response line should show a slope of unity. When suitable precautions were taken to ensure thorough dispersion of donor cells, it was possible to verify the predicted relationship. The only qualification which should be attached to the conclusions concerns the possibility of co-operative action between two different cell types, one of which is very abundant relative to the other. With this proviso, it may be concluded that the individual focus observed in the CAM reaction does indeed result from the activity of a single cell.

Context-Specific Function of the Engineered Peptide Domain of PHP.B

2021 ◽  
Author(s):  
R. Alexander Martino ◽  
Edwin C. Fluck ◽  
Jacqueline Murphy ◽  
Qiang Wang ◽  
Henry Hoff ◽  
...  
Keyword(s):  
Amino Acid ◽  
Blood Brain Barrier ◽  
Receptor Binding ◽  
Cell Types ◽  
Structural Features ◽  
Protein Domain ◽  
Brain Barrier ◽  
Target Cells ◽  
Blood Brain ◽  
The Impact

One approach to improve the utility of adeno-associated virus (AAV)-based gene therapy is to engineer the AAV capsid to 1) overcome poor transport through tissue barriers and 2) redirect the broadly tropic AAV to disease-relevant cell types. Peptide- or protein-domain insertions into AAV surface loops can achieve both engineering goals by introducing a new interaction surface on the AAV capsid. However, we understand little about the impact of insertions on capsid structure and the extent to which engineered inserts depend on a specific capsid context to function. Here, we examine insert–capsid interactions for the engineered variant AAV9-PHP.B. The 7-amino-acid peptide insert in AAV9-PHP.B facilitates transport across the murine blood–brain barrier via binding to the receptor Ly6a. When transferred to AAV1, the engineered peptide does not bind Ly6a. Comparative structural analysis of AAV1-PHP.B and AAV9-PHP.B revealed that the inserted 7-amino-acid loop is highly flexible and has remarkably little impact on the surrounding capsid conformation. Our work demonstrates that Ly6a binding requires interactions with both the PHP.B peptide and specific residues from the AAV9 HVR VIII region. An AAV1-based vector that incorporates a larger region of AAV9-PHP.B—including the 7-amino-acid loop and adjacent HVR VIII amino acids—can bind to Ly6a and localize to brain tissue. However, unlike AAV9-PHP.B, this AAV1-based vector does not penetrate the blood–brain barrier. Here we discuss the implications for AAV capsid engineering and the transfer of engineered activities between serotypes. Importance Targeting AAV vectors to specific cellular receptors is a promising strategy for enhancing expression in target cells or tissues while reducing off-target transgene expression. The AAV9-PHP.B/Ly6a interaction provides a model system with a robust biological readout that can be interrogated to better understand the biology of AAV vectors’ interactions with target receptors. In this work, we analyzed the sequence and structural features required to successfully transfer the Ly6a receptor-binding epitope from AAV9-PHP.B to another capsid of clinical interest: AAV1. We found that AAV1- and AAV9-based vectors targeted to the same receptor exhibited different brain-transduction profiles. Our work suggests that, in addition to attachment-receptor binding, the capsid context in which this binding occurs is important for a vector’s performance.

scholarly journals The Microtubule Plus-End Proteins EB1 and Dynactin Have Differential Effects on Microtubule Polymerization

2003 ◽  
Vol 14 (4) ◽  
pp. 1405-1417 ◽  
Author(s):  
Lee A. Ligon ◽  
Spencer S. Shelly ◽  
Mariko Tokito ◽  
Erika L.F. Holzbaur
Keyword(s):  
Cultured Cells ◽  
Cell Types ◽  
Microtubule Dynamics ◽  
In Vitro Assays ◽  
Nucleation Effect ◽  
Microtubule Polymerization ◽  
The Individual ◽  
Different Cell Types ◽  
Dynactin Complex

Several microtubule-binding proteins including EB1, dynactin, APC, and CLIP-170 localize to the plus-ends of growing microtubules. Although these proteins can bind to microtubules independently, evidence for interactions among them has led to the hypothesis of a plus-end complex. Here we clarify the interaction between EB1 and dynactin and show that EB1 binds directly to the N-terminus of the p150Glued subunit. One function of a plus-end complex may be to regulate microtubule dynamics. Overexpression of either EB1 or p150Glued in cultured cells bundles microtubules, suggesting that each may enhance microtubule stability. The morphology of these bundles, however, differs dramatically, indicating that EB1 and dynactin may act in different ways. Disruption of the dynactin complex augments the bundling effect of EB1, suggesting that dynactin may regulate the effect of EB1 on microtubules. In vitro assays were performed to elucidate the effects of EB1 and p150Glued on microtubule polymerization, and they show that p150Gluedhas a potent microtubule nucleation effect, whereas EB1 has a potent elongation effect. Overall microtubule dynamics may result from a balance between the individual effects of plus-end proteins. Differences in the expression and regulation of plus-end proteins in different cell types may underlie previously noted differences in microtubule dynamics.

Insulin/IGF-I binding ratio in skeletal and cardiac muscles of vertebrates: a phylogenetic approach

1995 ◽  
Vol 269 (6) ◽  
pp. R1370-R1377 ◽  
Author(s):  
M. Parrizas ◽  
M. A. Maestro ◽  
N. Banos ◽  
I. Navarro ◽  
J. Planas ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Specific Binding ◽  
Insulin Binding ◽  
Unit Weight ◽  
Tyrosine Kinase Activity ◽  
Igf I ◽  
Cardiac Muscles ◽  
Specific Insulin

Insulin and insulin-like growth factor (IGF-I) receptor binding and tyrosine kinase activity were characterized in cardiac and skeletal muscles of several vertebrates. Specific insulin binding per unit weight of skeletal muscle was clearly higher in pigeon and rat than in ectothermic vertebrates (32 +/- 5 and 25 +/- 2.7%/100 mg initial tissue in pigeon and rat, respectively, vs. 4.4 +/- 0.2%/100 mg in carp samples). Insulin binding clearly predominated over IGF-I binding in skeletal muscle of endotherms (IGF-I binding was 7.7 +/- 0.5%/100 mg in rat). In ectothermic vertebrates the situation was reversed, and IGF-I binding was higher than insulin binding. In cardiac muscle, specific binding of both insulin and especially IGF-I was higher than the values found in skeletal muscle of the same species (IGF-I binding was 60 +/- 4, 103 +/- 2, and 20 +/- 3%/100 mg in carp, turtle, and rat, respectively). The tyrosine kinase activity of insulin and IGF-I receptors of all species studied presented basal phosphotransferase rates (250-1,600 fmol P.micrograms protein-1.30 min-1) and percentage of stimulation (150-520%) with clear differences between species. The present data suggest that insulin and IGF-I binding to skeletal and cardiac muscles change through the vertebrate scale in both quantity and activity.

scholarly journals Correlated Gene Modules Uncovered by Single-Cell Transcriptomics with High Detectability and Accuracy

2020 ◽  
Author(s):  
Alec R. Chapman ◽  
David F. Lee ◽  
Wenting Cai ◽  
Wenping Ma ◽  
Xiang Li ◽  
...  
Keyword(s):  
Steady State ◽  
Single Cell ◽  
Protein Interactions ◽  
Cancer Cell Line ◽  
Cell Types ◽  
Mrna Levels ◽  
Functional Understanding ◽  
Gene Modules ◽  
Cell Transcriptome ◽  
Different Cell Types

AbstractSingle cell transcriptome sequencing has become extremely useful for cell typing. However, such differential expression data has shed little light on regulatory relationships among genes. Here, by examining pairwise correlations between mRNA levels of any two genes under steady-state conditions, we uncovered correlated gene modules (CGMs), clusters of intercorrelated genes that carry out certain biological functions together. We report a novel single-cell RNA-seq method called MALBAC-DT with higher detectability and accuracy, allowing determination of the covariance matrix of the expressed mRNAs for a homogenous cell population. We observed a prevalence of positive correlations between pairs of genes, with higher correlations corresponding to higher likelihoods of protein-protein interactions. Some CGMs, such as the p53 module in a cancer cell line, are cell type specific, while others, such as the protein synthesis CGM, are shared by different cell types. CGMs distinguished direct targets of p53 and exposed different modes of regulation of these genes in different cell types. Our covariance analyses of steady-state fluctuations provides a powerful way to advance our functional understanding of gene-to-gene interactions.

scholarly journals Detection of receptors for sulfated polysaccharides in human placenta by biotinylated probes.

1988 ◽  
Vol 36 (9) ◽  
pp. 1097-1102 ◽  
Author(s):  
P L Debbage ◽  
W Lange ◽  
T Hellmann ◽  
H J Gabius
Keyword(s):  
Developmental Stage ◽  
Human Placenta ◽  
Binding Sites ◽  
Dermatan Sulfate ◽  
Specific Binding ◽  
Cell Types ◽  
Sulfated Polysaccharides ◽  
Stage Of Development ◽  
Different Cell Types ◽  
Biotinylated Probes

Histochemical detection of binding sites for sulfated polysaccharides believed to be important mediators within recognitive interactions was carried out by application of biotinylated probes such as heparin, native and desulfated fucoidan, dermatan sulfate, and two types of carrageenans. The probes were derivatized by mild cyanogen bromide activation and subsequent aminoalkylation to allow incorporation of biotin, inserted with an epsilon-aminocaproic acid spacer to reduce charge-related and steric impediments. Specific labeling could be detected in different cell types of human placenta, dependent on the developmental stage. Sulfated polysaccharides bound predominantly to leucocytes in full-term placenta, whereas demonstration of specific binding sites in decidua, syncytiotrophoblasts, and cytotrophoblasts was restricted primarily to heparin and, less intensely, fucoidan, although not desulfated fucoidan. Heparin binding in the placenta after 8 weeks of gestation was reduced for epithelia that, at this stage of development, revealed carrageenan binding sites. Fucoidan binding was at this developmental stage measurable only for leucocytes. These results provide definite histochemical evidence for the presence and developmental regulation of expression of receptors for sulfated polysaccharides in different cell types of human placenta.

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