scholarly journals Molecular analysis of the interaction of LCMV with its cellular receptor α-dystroglycan

2001 ◽  
Vol 155 (2) ◽  
pp. 301-310 ◽  
Author(s):  
Stefan Kunz ◽  
Noemí Sevilla ◽  
Dorian B. McGavern ◽  
Kevin P. Campbell ◽  
Michael B.A. Oldstone
Keyword(s):  
Binding Site ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Divalent Cations ◽  
Terminal Region ◽  
Cellular Receptor ◽  
Globular Domain ◽  
Cell Surface Molecule ◽  
Laminin 1

α-Dystroglycan (DG) has been identified as the cellular receptor for lymphocytic choriomeningitis virus (LCMV) and Lassa fever virus (LFV). This subunit of DG is a highly versatile cell surface molecule that provides a molecular link between the extracellular matrix (ECM) and a β-DG transmembrane component, which interacts with the actin-based cytoskeleton. In addition, DG exhibits a complex pattern of interaction with a wide variety of ECM and cellular proteins. In the present study, we characterized the binding of LCMV to α-DG and addressed the role of α-DG–associated host-derived proteins in virus infection. We found that the COOH-terminal region of α-DG's first globular domain and the NH2-terminal region of the mucin-related structures of α-DG together form the binding site for LCMV. The virus–α-DG binding unlike ECM α-DG interactions was not dependent on divalent cations. Despite such differences in binding, LCMV and laminin-1 use, in part, an overlapping binding site on α-DG, and the ability of an LCMV isolate to compete with laminin-1 for receptor binding is determined by its binding affinity to α-DG. This competition of the virus with ECM molecules for receptor binding likely explains the recently found correlation between the affinity of LCMV binding to α-DG, tissue tropism, and pathological potential. LCMV strains and variants with high binding affinity to α-DG but not low affinity binders are able to infect CD11c+ dendritic cells, which express α-DG at their surface. Infection followed by dysfunction of these antigen-presenting cells contributes to immunosuppression and persistent viral infection in vivo.

In Vitro Androgen Receptor Binding Affinity and in Vivo Inhibitory Activity of 5?-Pregnane-3, 20-Dione

1988 ◽  
Vol 529 (1 Fourth Colloq) ◽  
pp. 239-241
Author(s):  
SAUDHAMINI PARTHASARATHY ◽  
ANDREA CHIN ◽  
VIRGINIA MALLOY ◽  
JONATHAN MATIAS
Keyword(s):  
Androgen Receptor ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Inhibitory Activity ◽  
Receptor Binding Affinity

Connectin, a target of homeotic gene control in Drosophila

Development ◽  
1992 ◽  
Vol 116 (4) ◽  
pp. 1163-1174 ◽  
Author(s):  
A.P. Gould ◽  
R.A. White
Keyword(s):  
Binding Site ◽  
Regulatory Region ◽  
Protein Product ◽  
Homeotic Gene ◽  
Homeotic Genes ◽  
Cell Surface Molecule ◽  
In Vivo Binding ◽  
Mediate Cell ◽  
Cell Cell

The homeotic genes of Drosophila encode transcription factors that specify morphological differences between segments. To identify the genes that they control, we developed a chromatin immunopurification approach designed to isolate in vivo binding sites for the products of the homeotic gene Ultrabithorax. Here, we report the analysis of one immunopurified binding site. This 110 bp fragment maps within a regulatory region of a gene under homeotic control, connectin. A 4 kb DNA fragment, including the immunopurified binding site, is sufficient to reproduce the appropriate homeotic control within a subset of the full tissue distribution of connectin. Analysis of the role of the 110 bp binding site indicates that it mediates transcriptional controls by Ultrabithorax and other homeotic genes. This is the first report of a functional in vivo binding site isolated using the chromatin immunopurification method. We also show that the protein product of the connectin gene is predicted to be a cell-surface molecule containing leucine-rich repeats. The protein, connectin, can mediate cell-cell adhesion thus suggesting a direct link between homeotic gene function and processes of cell-cell recognition.

scholarly journals Loss of the N-Linked Glycan at Residue 173 of Human Parainfluenza Virus Type 1 Hemagglutinin-Neuraminidase Exposes a Second Receptor-Binding Site

2008 ◽  
Vol 82 (17) ◽  
pp. 8400-8410 ◽  
Author(s):  
Irina V. Alymova ◽  
Garry Taylor ◽  
Vasiliy P. Mishin ◽  
Makiko Watanabe ◽  
K. Gopal Murti ◽  
...  
Keyword(s):  
Binding Site ◽  
Receptor Binding ◽  
Sendai Virus ◽  
Receptor Binding Site ◽  
Parainfluenza Viruses ◽  
Mutant Sequence ◽  
Lethal Infection ◽  
Human Parainfluenza Virus

ABSTRACT BCX 2798 (4-azido-5-isobutyrylamino-2,3-didehydro-2,3,4,5-tetradeoxy-d-glycero-d-galacto-2-nonulopyranosic acid) effectively inhibited the activities of the hemagglutinin-neuraminidase (HN) of human parainfluenza viruses (hPIV) in vitro and protected mice from lethal infection with a recombinant Sendai virus whose HN was replaced with that of hPIV-1 (rSeV[hPIV-1HN]) (I. V. Alymova, G. Taylor, T. Takimoto, T. H. Lin., P. Chand, Y. S. Babu, C. Li, X. Xiong, and A. Portner, Antimicrob. Agents Chemother. 48:1495-1502, 2004). The ability of BCX 2798 to select drug-resistant variants in vivo was examined. A variant with an Asn-to-Ser mutation at residue 173 (N173S) in HN was recovered from mice after a second passage of rSeV(hPIV-1HN) in the presence of BCX 2798 (10 mg/kg of body weight daily). The N173S mutant remained sensitive to BCX 2798 in neuraminidase inhibition assays but was more than 10,000-fold less sensitive to the compound in hemagglutination inhibition tests than rSeV(hPIV-1HN). Its susceptibility to BCX 2798 in plaque reduction assays was reduced fivefold and did not differ from that of rSeV(hPIV-1HN) in mice. The N173S mutant failed to be efficiently eluted from erythrocytes and released from cells. It demonstrated reduced growth in cell culture and superior growth in mice. The results for gel electrophoresis analysis were consistent with the loss of the N-linked glycan at residue 173 in the mutant. Sequence and structural comparisons revealed that residue 173 on hPIV-1 HN is located close to the region of the second receptor-binding site identified in Newcastle disease virus HN. Our study suggests that the N-linked glycan at residue 173 masks a second receptor-binding site on hPIV-1 HN.

scholarly journals Improved Glucose Metabolism In Vitro and In Vivo by an Allosteric Monoclonal Antibody That Increases Insulin Receptor Binding Affinity

PLoS ONE ◽  
2014 ◽  
Vol 9 (2) ◽  
pp. e88684 ◽  
Author(s):  
John A. Corbin ◽  
Vinay Bhaskar ◽  
Ira D. Goldfine ◽  
Daniel H. Bedinger ◽  
Angela Lau ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Glucose Metabolism ◽  
Insulin Receptor ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Receptor Binding Affinity ◽  
Insulin Receptor Binding

scholarly journals Fc-GDF15 glyco-engineering and receptor binding affinity optimization for body weight regulation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ella Fung ◽  
Liya Kang ◽  
Diana Sapashnik ◽  
Susan Benard ◽  
Annette Sievers ◽  
...  
Keyword(s):  
Weight Loss ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Half Life ◽  
Metabolic Diseases ◽  
Single Point ◽  
Life Extension ◽  
Single Point Mutation ◽  
Receptor Binding Site

AbstractGDF15 is a distant TGF-β family member that induces anorexia and weight loss. Due to its function, GDF15 has attracted attention as a potential therapeutic for the treatment of obesity and its associated metabolic diseases. However, the pharmacokinetic and physicochemical properties of GDF15 present several challenges for its development as a therapeutic, including a short half-life, high aggregation propensity, and protease susceptibility in serum. Here, we report the design, characterization and optimization of GDF15 in an Fc-fusion protein format with improved therapeutic properties. Using a structure-based engineering approach, we combined knob-into-hole Fc technology and N-linked glycosylation site mutagenesis for half-life extension, improved solubility and protease resistance. In addition, we identified a set of mutations at the receptor binding site of GDF15 that show increased GFRAL binding affinity and led to significant half-life extension. We also identified a single point mutation that increases p-ERK signaling activity and results in improved weight loss efficacy in vivo. Taken together, our findings allowed us to develop GDF15 in a new therapeutic format that demonstrates better efficacy and potential for improved manufacturability.

scholarly journals Evidence for the location of the receptor-binding site of human erythropoietin at the carboxyl-terminal domain

Blood ◽  
1991 ◽  
Vol 77 (6) ◽  
pp. 1203-1210 ◽  
Author(s):  
MR Fibi ◽  
W Stuber ◽  
P Hintz-Obertreis ◽  
G Luben ◽  
D Krumwieh ◽  
...  
Keyword(s):  
Binding Site ◽  
Receptor Binding ◽  
Terminal Region ◽  
Biologically Active ◽  
Receptor Binding Site ◽  
Specific Antibodies ◽  
Amino Terminal ◽  
Human Erythropoietin ◽  
A Cell ◽  
Carboxyl Terminal

Abstract Five different peptides (P1: 84′95; P2: 152′166; P3: 52′63; P4: 7′23; P5: 110′123) homologous to relatively hydrophilic regions of human erythropoietin (huEpo) have been synthesized to identify biologically active domains of the hormone. All peptides were able to induce high titers of peptide-specific antibodies in rabbits. Antisera from rabbits induced by recombinant huEpo (rhuEpo) contained a relatively high amount of antibodies preferentially directed against three peptides (P2, P4, and P5), of which P4 comprised the amino-terminal region, P2 the carboxyl-terminus, and P5 an interior region previously described as the receptor-binding site. The same three peptides were able to induce rhuEpo-specific antibodies, whereas P1 and P3 lacked this activity. Only peptide-P2-induced antisera inhibited the biologic activity of rhuEpo in a cell proliferation assay, indicating that the carboxyl-terminal region of the molecule is essentially involved in the biologic function of rhuEpo.

scholarly journals Cleavage of K-FGF produces a truncated molecule with increased biological activity and receptor binding affinity.

1993 ◽  
Vol 121 (3) ◽  
pp. 705-713 ◽  
Author(s):  
P Bellosta ◽  
D Talarico ◽  
D Rogers ◽  
C Basilico
Keyword(s):  
Amino Acids ◽  
Biological Activity ◽  
Growth Factor ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Biologically Active ◽  
Heparin Binding ◽  
Wild Type ◽  
Mammalian Expression

The K-FGF/HST (FGF-4) growth factor is a member of the FGF family which is efficiently secreted and contains a single N-linked glycosylation signal. To study the role of glycosylation in the secretion of K-FGF, we mutated the human K-fgf cDNA to eliminate the glycosylation signal and the mutated cDNA was cloned into a mammalian expression vector. Studies of immunoprecipitation from the conditioned medium of cells expressing this plasmid revealed that the lack of glycosylation did not impair secretion, however the unglycosylated protein was immediately cleaved into two NH2-terminally truncated peptides of 13 and 15 kD, which appeared to be more biologically active than the wild-type protein. These two proteins also showed higher heparin binding affinity than that of wt K-FGF. We have expressed in bacteria the larger of these two proteins (K140), in which the NH2-terminal 36 amino acids present in the mature form of K-FGF have been deleted. Mitogenicity assays on several cell lines showed that purified recombinant K140 had approximately five times higher biological activity than wild-type recombinant K-FGF. Studies of receptor binding showed that K140 had higher affinity than wt K-FGF for two of the four members of FGF receptor's family, specifically for FGFR-1 (flg) and FGFR-2 (bek). K140 also had increased heparin binding ability, but this property does not appear to be responsible for the increased affinity for FGF receptors. Thus removal of the NH2-terminal 36 amino acids from the mature K-FGF produces growth factor molecules with an altered conformation, resulting in higher heparin affinity, and more efficient binding to FGF receptors. Although it is not clear whether cleavage of K-FGF to generate K140 occurs in vivo, this could represent a novel mechanism of modulation of growth factor activity.

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