scholarly journals Structural basis for regulation of human calcium-sensing receptor by magnesium ions and an unexpected tryptophan derivative co-agonist

2016 ◽  
Vol 2 (5) ◽  
pp. e1600241 ◽  
Author(s):  
Chen Zhang ◽  
Tuo Zhang ◽  
Juan Zou ◽  
Cassandra Lynn Miller ◽  
Rakshya Gorkhali ◽  
...  
Keyword(s):  
Amino Acids ◽  
Divalent Cations ◽  
Aromatic Amino Acids ◽  
Structural Basis ◽  
Guanine Nucleotide Binding Protein ◽  
Functional Studies ◽  
Calcium Sensing ◽  
Physiological Processes ◽  
Extracellular Stimuli ◽  
Guanine Nucleotide Binding

Ca2+-sensing receptors (CaSRs) modulate calcium and magnesium homeostasis and many (patho)physiological processes by responding to extracellular stimuli, including divalent cations and amino acids. We report the first crystal structure of the extracellular domain (ECD) of human CaSR bound with Mg2+ and a tryptophan derivative ligand at 2.1 Å. The structure reveals key determinants for cooperative activation by metal ions and aromatic amino acids. The unexpected tryptophan derivative was bound in the hinge region between two globular ECD subdomains, and represents a novel high-affinity co-agonist of CaSR. The dissection of structure-function relations by mutagenesis, biochemical, and functional studies provides insights into the molecular basis of human diseases arising from CaSR mutations. The data also provide a novel paradigm for understanding the mechanism of CaSR-mediated signaling that is likely shared by the other family C GPCR [G protein (heterotrimeric guanine nucleotide–binding protein)–coupled receptor] members and can facilitate the development of novel CaSR-based therapeutics.

scholarly journals No evidence for a bone phenotype in GPRC6A knockout mice under normal physiological conditions

2008 ◽  
Vol 42 (3) ◽  
pp. 215-223 ◽  
Author(s):  
Petrine Wellendorph ◽  
Lars Dan Johansen ◽  
Anders A Jensen ◽  
Emilio Casanova ◽  
Martin Gassmann ◽  
...  
Keyword(s):  
Amino Acids ◽  
Knockout Mice ◽  
Divalent Cations ◽  
Physiological Role ◽  
Bone Homeostasis ◽  
Wild Type ◽  
Mineral Density ◽  
Calcium Sensing ◽  
Wide Range ◽  
Mammalian Tissues

GPRC6A is a seven-transmembrane receptor mediating signaling by a wide range of l-α-amino acids, a signaling augmented by the divalent cations Ca2+ and Mg2+. GPRC6A transcripts are detected in numerous mammalian tissues, but the physiological role of the receptor is thus far elusive. Analogously to the closely related calcium-sensing receptor, GPRC6A has been proposed to function as a metabolic sensor of Ca2+ and amino acids in bone and other tissues. In the present study, we have generated the first GPRC6A knockout mice and studied their phenotype with particular focus on bone homeostasis. The generated GPRC6A knockout mice are viable and fertile, develop normally, and exhibit no significant differences in body weight compared with wild-type littermates. Assessment of bone mineral density, histomorphometry, and bone metabolism demonstrated no significant differences between 13-week-old knockout and wild-type mice. In conclusion, our data do not support a role for GPRC6A in normal bone physiology.

scholarly journals Identification of Binding Proteins for TSC22D1 Family Proteins Using Mass Spectrometry

2021 ◽  
Vol 22 (20) ◽  
pp. 10913
Author(s):  
Ryouta Kamimura ◽  
Daisuke Uchida ◽  
Shin-ichiro Kanno ◽  
Ryo Shiraishi ◽  
Toshiki Hyodo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Binding Proteins ◽  
Guanine Nucleotide ◽  
Binding Assays ◽  
Guanine Nucleotide Binding Protein ◽  
Cell Systems ◽  
Guanine Nucleotide Binding

TSC-22 (TGF-β stimulated clone-22) has been reported to induce differentiation, growth inhibition, and apoptosis in various cells. TSC-22 is a member of a family in which many proteins are produced from four different family genes. TSC-22 (corresponding to TSC22D1-2) is composed of 144 amino acids translated from a short variant mRNA of the TSC22D1 gene. In this study, we attempted to determine the intracellular localizations of the TSC22D1 family proteins (TSC22D1-1, TSC-22 (TSC22D1-2), and TSC22(86) (TSC22D1-3)) and identify the binding proteins for TSC22D1 family proteins by mass spectrometry. We determined that TSC22D1-1 was mostly localized in the nucleus, TSC-22 (TSC22D1-2) was localized in the cytoplasm, mainly in the mitochondria and translocated from the cytoplasm to the nucleus after DNA damage, and TSC22(86) (TSC22D1-3) was localized in both the cytoplasm and nucleus. We identified multiple candidates of binding proteins for TSC22D1 family proteins in in vitro pull-down assays and in vivo binding assays. Histone H1 bound to TSC-22 (TSC22D1-2) or TSC22(86) (TSC22D1-3) in the nucleus. Guanine nucleotide-binding protein-like 3 (GNL3), which is also known as nucleostemin, bound to TSC-22 (TSC22D1-2) in the nucleus. Further investigation of the interaction of the candidate binding proteins with TSC22D1 family proteins would clarify the biological roles of TSC22D1 family proteins in several cell systems.

scholarly journals Activity of selected aromatic amino acids in biological systems.

2011 ◽  
Vol 58 (4) ◽  
Author(s):  
Wirginia Krzyściak
Keyword(s):  
Amino Acids ◽  
Aromatic Amino Acids ◽  
Structural Function ◽  
Human Organism ◽  
Physiological Processes ◽  
Comprehensive Knowledge ◽  
Chronic Kidney Insufficiency ◽  
Kidney Insufficiency ◽  
Disease Entities ◽  
Bipolar Affective Disorders

Besides the structural function in proteins, aromatic amino acids are precursors of many important biological compounds essential for normal functioning of the human organism. Many of these compounds may be used as markers for identification of specific pathological states. Comprehensive knowledge about the metabolism of aromatic amino acids and mechanisms of action of their metabolites made it possible to develop effective treatments for many disorders. However, it should not be forgotten that in some pathological conditions, these compounds could not only be involved in the pathogenesis of many disease entities but could also be used as an important tool in prediction of many diseases. This paper contains a review of published literature on aromatic amino acids in the context of physiological processes of the human body and chosen social disorders, such as cancers; psychiatric disorders: depression, anxiety states, schizophrenia, bipolar affective disorders; neurodegenerative, and cardiovascular diseases; chronic kidney insufficiency or diabetes.

scholarly journals Purification and characterization of predominant G-protein from bovine lung membranes. Biochemical and immunochemical comparison with Gi1 and Go purified from brain

1989 ◽  
Vol 259 (2) ◽  
pp. 499-506 ◽  
Author(s):  
Y Kanaho ◽  
S T Crooke ◽  
J M Stadel
Keyword(s):  
G Protein ◽  
Polyacrylamide Gel Electrophoresis ◽  
Nucleotide Binding ◽  
Rabbit Brain ◽  
Subunit Structure ◽  
Guanine Nucleotide Binding Protein ◽  
Functional Studies ◽  
Coomassie Blue ◽  
Rate Of Hydrolysis ◽  
Guanine Nucleotide Binding

The predominant guanine nucleotide-binding protein (G-protein) of bovine lung membranes, termed GL, has been purified and compared biochemically, immunochemically and functionally with Gi and Go purified from rabbit brain. The purified GL appeared to have a similar subunit structure to Gi and Go, being composed of alpha, beta and possibly gamma subunits. On Coomassie Blue-stained SDS/polyacrylamide gels and immunoblots, the alpha subunit of GL (GL alpha) displayed an intermediate mobility (40 kDa) between those of Gi and Go (Gi alpha and Go alpha). GL alpha was [32P]ADP-ribosylated in the presence of pertussis toxin and [32P]NAD+. Analysis of [32P]ADP-ribosylated alpha subunits by SDS/polyacrylamide-gel electrophoresis and isoelectric focusing showed that GL alpha was distinct from Gi alpha and Go alpha, but very similar to the predominant G-protein in neutrophil membranes. Immunochemical characterization also revealed that GL was distinct from Gi and Go, but was indistinguishable from the G-protein of neutrophils, which has been tentatively identified as Gi2 [Goldsmith, Gierschik, Milligan, Unson, Vinitsky, Maleck & Spiegel (1987) J. Biol. Chem. 262, 14683-14688]. In functional studies, higher Mg2+ concentrations were required for guanosine 5'-[gamma-[35S]thio]triphosphate (GTP[35S]) binding to GL than were required for nucleotide binding to Go, whereas Gi showed a Mg2+-dependence similar to that of GL. The kinetics of GTP[35S] binding to GL was quite different from those of Gi and Go; t1/2 values of maximal binding were 30, 15 and 5 min respectively. In contrast, the rate of hydrolysis of [gamma-32P]GTP by GL (t1/2 approximately 1 min) was approx. 4 times faster than that by Gi or Go. These results indicated that the predominant G-protein purified from lung is structurally and functionally distinct from Gi and Go of brain, but structurally indistinguishable from Gi2 of neutrophils.

scholarly journals Structural Basis for Metallic-Like Conductivity in Microbial Nanowires

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Nikhil S. Malvankar ◽  
Madeline Vargas ◽  
Kelly Nevin ◽  
Pier-Luc Tremblay ◽  
Kenneth Evans-Lutterodt ◽  
...  
Keyword(s):  
Amino Acids ◽  
Electron Transport ◽  
Aromatic Amino Acids ◽  
Geobacter Sulfurreducens ◽  
Experimental Results ◽  
Structural Basis ◽  
Ph Change ◽  
Long Distance ◽  
Content Type ◽  
X Ray

ABSTRACT Direct measurement of multiple physical properties of Geobacter sulfurreducens pili have demonstrated that they possess metallic-like conductivity, but several studies have suggested that metallic-like conductivity is unlikely based on the structures of the G. sulfurreducens pilus predicted from homology models. In order to further evaluate this discrepancy, pili were examined with synchrotron X-ray microdiffraction and rocking-curve X-ray diffraction. Both techniques revealed a periodic 3.2-Å spacing in conductive, wild-type G. sulfurreducens pili that was missing in the nonconductive pili of strain Aro5, which lack key aromatic acids required for conductivity. The intensity of the 3.2-Å peak increased 100-fold when the pH was shifted from 10.5 to 2, corresponding with a previously reported 100-fold increase in pilus conductivity with this pH change. These results suggest a clear structure-function correlation for metallic-like conductivity that can be attributed to overlapping π-orbitals of aromatic amino acids. A homology model of the G. sulfurreducens pilus was constructed with a Pseudomonas aeruginosa pilus model as a template as an alternative to previous models, which were based on a Neisseria gonorrhoeae pilus structure. This alternative model predicted that aromatic amino acids in G. sulfurreducens pili are packed within 3 to 4 Å, consistent with the experimental results. Thus, the predictions of homology modeling are highly sensitive to assumptions inherent in the model construction. The experimental results reported here further support the concept that the pili of G. sulfurreducens represent a novel class of electronically functional proteins in which aromatic amino acids promote long-distance electron transport. IMPORTANCE The mechanism for long-range electron transport along the conductive pili of Geobacter sulfurreducens is of interest because these “microbial nanowires” are important in biogeochemical cycling as well as applications in bioenergy and bioelectronics. Although proteins are typically insulators, G. sulfurreducens pilus proteins possess metallic-like conductivity. The studies reported here provide important structural insights into the mechanism of the metallic-like conductivity of G. sulfurreducens pili. This information is expected to be useful in the design of novel bioelectronic materials.

scholarly journals What We Know and What We Need to Know about Aromatic and Cationic Biogenic Amines in the Gastrointestinal Tract

Foods ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 145 ◽  
Author(s):  
Alberto Fernández-Reina ◽  
José Urdiales ◽  
Francisca Sánchez-Jiménez
Keyword(s):  
Amino Acids ◽  
Immune Response ◽  
Gastrointestinal Tract ◽  
Biogenic Amines ◽  
Aromatic Amino Acids ◽  
Signalling Pathways ◽  
Physiological Effects ◽  
Cellular Receptors ◽  
Physiological Processes ◽  
Molecular Information

Biogenic amines derived from basic and aromatic amino acids (B/A-BAs), polyamines, histamine, serotonin, and catecholamines are a group of molecules playing essential roles in many relevant physiological processes, including cell proliferation, immune response, nutrition and reproduction. All these physiological effects involve a variety of tissue-specific cellular receptors and signalling pathways, which conforms to a very complex network that is not yet well-characterized. Strong evidence has proved the importance of this group of molecules in the gastrointestinal context, also playing roles in several pathologies. This work is based on the hypothesis that integration of biomedical information helps to reach new translational actions. Thus, the major aim of this work is to combine scientific knowledge on biomolecules, metabolism and physiology of the main B/A-BAs involved in the pathophysiology of the gastrointestinal tract, in order to point out important gaps in information and other facts deserving further research efforts in order to connect molecular information with pathophysiological observations.

408 Aromatic amino acids alleviate intestinal inflammation in piglets through calcium-sensing receptor activation

2017 ◽  
Vol 95 (suppl_4) ◽  
pp. 201-202 ◽  
Author(s):  
B. Tan ◽  
B. Huang ◽  
J. Wang ◽  
G. P. Guang ◽  
C. B. Yang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Intestinal Inflammation ◽  
Aromatic Amino Acids ◽  
Receptor Activation ◽  
Calcium Sensing Receptor ◽  
Calcium Sensing

The Efficient Preparation of Radiolabeled Aromatic Amino Acids via Cu-Mediated Radiofluorination using Ni-complexes

2019 ◽  
Author(s):  
A Craig ◽  
N Kolks ◽  
E Urusova ◽  
BD Zlatopolskiy ◽  
B Neumaier
Keyword(s):  
Amino Acids ◽  
Aromatic Amino Acids
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