scholarly journals New Naturally Occurring Missense Mutations of the Human Mineralocorticoid Receptor Disclose Important Residues Involved in Dynamic Interactions with Deoxyribonucleic Acid, Intracellular Trafficking, and Ligand Binding

2004 ◽  
Vol 18 (9) ◽  
pp. 2151-2165 ◽  
Author(s):  
Paola Sartorato ◽  
Françoise Cluzeaud ◽  
Jérôme Fagart ◽  
Say Viengchareun ◽  
Marc Lombès ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Intracellular Trafficking ◽  
Mineralocorticoid Receptor ◽  
Deoxyribonucleic Acid ◽  
Missense Mutations ◽  
Dynamic Interactions ◽  
Naturally Occurring

scholarly journals Functional Characterization of Naturally Occurring Pathogenic Mutations in the Human Leptin Receptor

Endocrinology ◽  
2008 ◽  
Vol 149 (12) ◽  
pp. 6043-6052 ◽  
Author(s):  
Wendy Kimber ◽  
Frank Peelman ◽  
Xavier Prieur ◽  
Teresia Wangensteen ◽  
Stephen O'Rahilly ◽  
...  
Keyword(s):  
Cell Surface ◽  
Ligand Binding ◽  
Binding Site ◽  
Molecular Mechanisms ◽  
Leptin Receptor ◽  
Receptor Activation ◽  
Cell Surface Expression ◽  
Missense Mutations ◽  
Naturally Occurring

We have recently reported the first naturally occurring missense mutations in the leptin receptor (LR) in patients with severe obesity. We have examined the molecular mechanisms by which these extracellular domain mutations disrupt LR signaling. The Ala409Glu mutant receptor is expressed at the cell surface, binds leptin normally but fails to signal to downstream pathways. A409 is present on the surface-exposed region of the Ig-like domain that forms the binding site III for interaction with leptin. This binding site does not appear to contribute to the binding affinity of leptin to its receptor but is critical for receptor activation in response to ligand binding. The Trp664Arg and His684Pro mutations are predicted to impair receptor folding. Both mutants result in a complete inability to signal to downstream pathways despite evidence for some residual cell surface expression and ligand binding. The Arg612His mutant falls in the second subdomain of the high-affinity binding site for leptin, and results in a receptor that shows evidence for intracellular retention but retains some residual signaling. These studies, which represent the first detailed characterization of the functional properties of naturally occurring missense mutations in the human LR, indicate that most such mutations affect receptor folding and expression at the cell surface rather than primarily impairing ligand binding. The exception is Ala409Glu, which interferes with the coupling of ligand binding to receptor activation. Naturally occurring mutations associated with human obesity are valuable tools with which to explore structure/function relationships within the LR.

scholarly journals Naturally-occurring missense mutations in the human growth hormone-releasing hormone receptor alter ligand binding

2005 ◽  
Vol 186 (3) ◽  
pp. 515-521 ◽  
Author(s):  
Maria Alba ◽  
Roberto Salvatori
Keyword(s):  
Growth Hormone ◽  
Ligand Binding ◽  
Transmembrane Domain ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Common Mechanism ◽  
Missense Mutations ◽  
Binding Studies ◽  
Releasing Hormone ◽  
Naturally Occurring

Growth hormone (GH) releasing hormone (GHRH) is a hypothalamic factor that stimulates GH secretion. It acts by activating a seven transmembrane domain G protein-coupled receptor of 423 amino acids expressed by the somatotroph cells of the pituitary gland (GHRH receptor, GHRH-R). Familial isolated growth hormone deficiency (IGHD) can be caused by mutations in the GHRH-R gene both in humans and mice. We have described six disease-causing missense mutations in this gene in IGHD patients (H137L, L144H, A176V, A222E, F242C, K329E). These mutations are inherited as autosomal recessive traits, and cause impairment of the receptor to transmit GHRH signalling. The aim of this study is to investigate the mechanisms through which these mutations cause receptor malfunction. To this end, we transiently expressed each mutated receptor into Chinese hamster ovary cells. Cells expressing each of the mutated receptors did not show an increase in intracellular cyclic AMP in response to GHRH. Immunoprecipitation and immunofluorescence studies indicated that the amino acid changes do not cause protein degradation, and do not alter the proper insertion of the receptor into the cell membrane. Binding studies with human 125I-GHRH showed that the lack of response to GHRH is due to inability of all the mutated receptors to bind the ligand. These studies demonstrate that abnormal ligand binding is a common mechanism by which naturally occurring missense mutation alter GHRH-R function.

Consequences of two naturally occurring missense mutations in the structure and function of Bruton agammaglobulinemia tyrosine kinase

IUBMB Life ◽  
2012 ◽  
Vol 64 (4) ◽  
pp. 346-353 ◽  
Author(s):  
Alexander Vargas-Hernández ◽  
Gabriela López-Herrera ◽  
José L. Maravillas-Montero ◽  
Felipe Vences-Catalán ◽  
Dolores Mogica-Martínez ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Structure And Function ◽  
Missense Mutations ◽  
Naturally Occurring ◽  
And Function

A naturally occurring Tyr143HisαIIb mutation abolishes αIIbβ3 function for soluble ligands but retains its ability for mediating cell adhesion and clot retraction: comparison with other mutations causing ligand-binding defects

Blood ◽  
2003 ◽  
Vol 101 (9) ◽  
pp. 3485-3491 ◽  
Author(s):  
Teruo Kiyoi ◽  
Yoshiaki Tomiyama ◽  
Shigenori Honda ◽  
Seiji Tadokoro ◽  
Morio Arai ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Ligand Binding ◽  
Binding Sites ◽  
Clot Retraction ◽  
Naturally Occurring ◽  
Binding Function ◽  
293 Cells ◽  
Ligand Binding Sites ◽  
Functional Defect ◽  
And Function

The molecular basis for the interaction between a prototypic non–I-domain integrin, αIIbβ3, and its ligands remains to be determined. In this study, we have characterized a novel missense mutation (Tyr143His) in αIIb associated with a variant of Glanzmann thrombasthenia. Osaka-12 platelets expressed a substantial amount of αIIbβ3(36%-41% of control) but failed to bind soluble ligands, including a high-affinity αIIbβ3-specific peptidomimetic antagonist. Sequence analysis revealed that Osaka-12 is a compound heterozygote for a single 521T>C substitution leading to a Tyr143His substitution in αIIb and for the null expression of αIIb mRNA from the maternal allele. Given that Tyr143 is located in the W3 4-1 loop of the β-propeller domain of αIIb, we examined the effects of Tyr143His or Tyr143Ala substitution on the expression and function of αIIbβ3 and compared them with KO (Arg-Thr insertion between 160 and 161 residues of αIIb) and with the Asp163Ala mutation located in the same loop by using 293 cells. Each of them abolished the binding function of αIIbβ3 for soluble ligands without disturbing αIIbβ3 expression. Because immobilized fibrinogen and fibrin are higher affinity/avidity ligands for αIIbβ3, we performed cell adhesion and clot retraction assays. In sharp contrast to KO mutation and Asp163AlaαIIbβ3, Tyr143HisαIIbβ3-expressing cells still had some ability for cell adhesion and clot retraction. Thus, the functional defect induced by Tyr143HisαIIb is likely caused by its allosteric effect rather than by a defect in the ligand-binding site itself. These detailed structure–function analyses provide better understanding of the ligand-binding sites in integrins.

scholarly journals The role of amino acid α38 in the control of oxygen binding to human adult and embryonic haemoglobin Portland

1999 ◽  
Vol 343 (3) ◽  
pp. 681-685 ◽  
Author(s):  
Tao ZHENG ◽  
Thomas BRITTAIN ◽  
Nicholas J. WATMOUGH ◽  
Roy E. WEBER
Keyword(s):  
Amino Acid ◽  
Ligand Binding ◽  
Significant Contribution ◽  
Molecular Model ◽  
Site Directed Mutagenesis ◽  
Oxygen Binding ◽  
Naturally Occurring ◽  
Two State Model ◽  
T State

The role of the amino acid at position α38 in haemoglobin has been probed using site-directed mutagenesis. When the Thr residue at position α38 (which is totally conserved in all mammals) is changed to a Gln, the equilibrium properties of the protein are significantly altered. Equilibrium and kinetic data show that the R-state properties of the protein are essentially unaffected by the mutation whilst the allosteric equilibrium and T-state properties are changed. Mutation of the naturally occurring Gln38 of the human embryonic haemoglobin ζ-chain (the only known non-Thr containing globin) to a Thr residue shows the converse change in properties produced by the adult mutation, although in this case the situation is complicated by significant chain heterogeneity in the T state. An extension of the two-state model of co-operativity is presented to describe quantitatively the equilibrium ligand binding in the presence of T-state chain heterogeneity. A molecular model is described in which the putative interaction of αGln38 and βTyr145 is identified which make a significant contribution to the previously reported unusual ligand-binding properties of the ζ-chain containing human embryonic haemoglobins.

The Met852 Residue Is a Key Organizer of the Ligand-Binding Cavity of the Human Mineralocorticoid Receptor

2005 ◽  
Vol 67 (5) ◽  
pp. 1714-1722 ◽  
Author(s):  
Jérôme Fagart ◽  
Cendrine Seguin ◽  
Grégory Maurice Pinon ◽  
Marie-Edith Rafestin-Oblin
Keyword(s):  
Ligand Binding ◽  
Mineralocorticoid Receptor ◽  
Binding Cavity

scholarly journals Naturally Occurring CCR5 Extracellular and Transmembrane Domain Variants Affect HIV-1 Co-receptor and Ligand Binding Function

1999 ◽  
Vol 274 (23) ◽  
pp. 16228-16234 ◽  
Author(s):  
O. M. Zack Howard ◽  
Aiko-Konno Shirakawa ◽  
Jim A. Turpin ◽  
Andrew Maynard ◽  
Gregory J. Tobin ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Transmembrane Domain ◽  
Naturally Occurring ◽  
Binding Function ◽  
Hiv 1

scholarly journals CHANGING NUCLEAR HISTONE PATTERNS DURING DEVELOPMENT III. THE DEOXYRIBONUCLEIC ACID CONTENT OF SPERMATOGENIC CELLS IN THE CRAB EMERITA ANALOGA

1969 ◽  
Vol 17 (9) ◽  
pp. 591-600 ◽  
Author(s):  
J. C. VAUGHN ◽  
R. D. LOCY
Keyword(s):  
Deoxyribonucleic Acid ◽  
Rat Tissues ◽  
Spermatogenic Cells ◽  
Spectral Absorption ◽  
Naturally Occurring ◽  
Emerita Analoga ◽  
Dna Contents ◽  
Nuclear Histone ◽  
Sperm Nuclei ◽  
Sperm Maturity

The deoxyribonucleic acid (DNA) content of spermatogenic cells of the decapod crab, Emerita analoga, has been cytophotometrically determined at various stages of development, using Feulgen-stained nuclei. The haploid DNA value is found to be 2.9 x 10–12 g, regardless of the nuclear histone content, which drops to cytochemically indetectable levels by sperm maturity. In determining this value, a precise extinction coefficient for Feulgen-stained nuclei was first determined using chicken, frog and toad erythrocyte nuclei and also nuclei from various rat tissues. The effect of naturally occurring nuclear histone depletion on the quantitative Feulgen reaction has also been examined. Identical hydrolysis curves and Feulgen spectral absorption curves are found for somatic nuclei, which contain a full histone complement, and for mature sperm nuclei, which do not contain histones. Loss of nuclear histone does not lead to a change in total Feulgen dye bound per nucleus, as early, middle and late spermatids have equal DNA contents as reflected by Feulgen binding, and primary spermatocytes contain 4 times this value, as expected from the DNA constancy law. The effect of histones (and other proteins) on quantitative Feulgen microspectrophotometry is discussed.

scholarly journals Disease-associated missense mutations in GluN2B subunit alter NMDA receptor ligand binding and ion channel properties

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Laura Fedele ◽  
Joseph Newcombe ◽  
Maya Topf ◽  
Alasdair Gibb ◽  
Robert J. Harvey ◽  
...  
Keyword(s):  
Nmda Receptor ◽  
Ligand Binding ◽  
Ion Channel ◽  
Missense Mutations ◽  
Receptor Ligand ◽  
Ion Channel Properties ◽  
Channel Properties
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