scholarly journals An arrestin-1 surface opposite of its interface with photoactivated rhodopsin engages with enolase-1

2020 ◽  
Vol 295 (19) ◽  
pp. 6498-6508
Author(s):  
Connie Jaqueline Miranda ◽  
Nicole Fernandez ◽  
Nader Kamel ◽  
Daniel Turner ◽  
Del Benzenhafer ◽  
...  
Keyword(s):  
Amino Acids ◽  
Molecular Model ◽  
Signaling Cascades ◽  
Contact Sites ◽  
Binding Partners ◽  
Protein Partners ◽  
Fluorescence Quench ◽  
Selective Substitution ◽  
Additional Protein ◽  
G Protein Coupled

Arrestin-1 is the arrestin family member responsible for inactivation of the G protein–coupled receptor rhodopsin in photoreceptors. Arrestin-1 is also well-known to interact with additional protein partners and to affect other signaling cascades beyond phototransduction. In this study, we investigated one of these alternative arrestin-1 binding partners, the glycolysis enzyme enolase-1, to map the molecular contact sites between these two proteins and investigate how the binding of arrestin-1 affects the catalytic activity of enolase-1. Using fluorescence quench protection of strategically placed fluorophores on the arrestin-1 surface, we observed that arrestin-1 primarily engages enolase-1 along a surface that is opposite of the side of arrestin-1 that binds photoactivated rhodopsin. Using this information, we developed a molecular model of the arrestin-1–enolase-1 complex, which was validated by targeted substitutions of charge-pair interactions. Finally, we identified the likely source of arrestin's modulation of enolase-1 catalysis, showing that selective substitution of two amino acids in arrestin-1 can completely remove its effect on enolase-1 activity while still remaining bound to enolase-1. These findings open up opportunities for examining the functional effects of arrestin-1 on enolase-1 activity in photoreceptors and their surrounding cells.

scholarly journals Regulation of mTORC1 by Upstream Stimuli

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 989
Author(s):  
Chase H. Melick ◽  
Jenna L. Jewell
Keyword(s):  
Amino Acids ◽  
Growth Factors ◽  
Control Cell ◽  
Mammalian Target Of Rapamycin ◽  
Small Gtpases ◽  
G Protein Coupled Receptors ◽  
Signaling Cascades ◽  
Growth Metabolism ◽  
Mtor Complex 1 ◽  
G Protein Coupled

The mammalian target of rapamycin (mTOR) is an evolutionary conserved Ser/Thr protein kinase that senses multiple upstream stimuli to control cell growth, metabolism, and autophagy. mTOR is the catalytic subunit of mTOR complex 1 (mTORC1). A significant amount of research has uncovered the signaling pathways regulated by mTORC1, and the involvement of these signaling cascades in human diseases like cancer, diabetes, and ageing. Here, we review advances in mTORC1 regulation by upstream stimuli. We specifically focus on how growth factors, amino acids, G-protein coupled receptors (GPCRs), phosphorylation, and small GTPases regulate mTORC1 activity and signaling.

What Evolutionary Evidence Implies About the Identity of the Mechanoelectrical Couplers in Vascular Smooth Muscle Cells

Physiology ◽  
2021 ◽  
Vol 36 (5) ◽  
pp. 292-306
Author(s):  
Heather A. Drummond
Keyword(s):  
Transient Receptor Potential ◽  
Molecular Model ◽  
Receptor Potential ◽  
Transient Receptor Potential Channels ◽  
Potential Channels ◽  
Transient Receptor ◽  
Paradigm Shifting ◽  
G Protein Coupled ◽  
Evolutionary Role

Loss of pressure-induced vasoconstriction increases susceptibility to renal and cerebral vascular injury. Favored paradigms underlying initiation of the response include transient receptor potential channels coupled to G protein-coupled receptors or integrins as transducers. Degenerin channels may also mediate the response. This review addresses the 1) evolutionary role of these molecules in mechanosensing, 2) limitations to identifying mechanosensitive molecules, and 3) paradigm shifting molecular model for a VSMC mechanosensor.

scholarly journals G protein-coupled receptors--recent advances.

2012 ◽  
Vol 59 (4) ◽  
Author(s):  
Dorota Latek ◽  
Anna Modzelewska ◽  
Bartosz Trzaskowski ◽  
Krzysztof Palczewski ◽  
Sławomir Filipek
Keyword(s):  
G Protein ◽  
Biochemical Characterization ◽  
Membrane Receptors ◽  
Signaling Cascades ◽  
Protein Signaling ◽  
Partial Activation ◽  
Bovine Rhodopsin ◽  
G Protein Coupled ◽  
Multiple Ligand

The years 2000 and 2007 witnessed milestones in current understanding of G protein-coupled receptor (GPCR) structural biology. In 2000 the first GPCR, bovine rhodopsin, was crystallized and the structure was solved, while in 2007 the structure of β(2)-adrenergic receptor, the first GPCR with diffusible ligands, was determined owing to advances in microcrystallization and an insertion of the fast-folding lysozyme into the receptor. In parallel with those crystallographic studies, the biological and biochemical characterization of GPCRs has advanced considerably because those receptors are molecular targets for many of currently used drugs. Therefore, the mechanisms of activation and signal transduction to the cell interior deduced from known GPCRs structures are of the highest importance for drug discovery. These proteins are the most diversified membrane receptors encoded by hundreds of genes in our genome. They participate in processes responsible for vision, smell, taste and neuronal transmission in response to photons or binding of ions, hormones, peptides, chemokines and other factors. Although the GPCRs share a common seven-transmembrane α-helical bundle structure their binding sites can accommodate thousands of different ligands. The ligands, including agonists, antagonists or inverse agonists change the structure of the receptor. With bound agonists they can form a complex with a suitable G protein, be phosphorylated by kinases or bind arrestin. The discovered signaling cascades invoked by arrestin independently of G proteins makes the GPCR activating scheme more complex such that a ligand acting as an antagonist for G protein signaling can also act as an agonist in arrestin-dependent signaling. Additionally, the existence of multiple ligand-dependent partial activation states as well as dimerization of GPCRs result in a 'microprocessor-like' action of these receptors rather than an 'on-off' switch as was commonly believed only a decade ago.

scholarly journals Prospects for use of peptides and their derivatives, structurally corresponding to the G protein-coupled receptors, in medicine

2015 ◽  
Vol 61 (1) ◽  
pp. 19-29 ◽  
Author(s):  
A.O. Shpakov ◽  
E.A. Shpakova
Keyword(s):  
G Protein ◽  
Intracellular Signaling ◽  
High Efficiency ◽  
Clinical Medicine ◽  
Inflammatory Diseases ◽  
G Protein Coupled Receptors ◽  
Signaling Cascades ◽  
G Protein Coupled

The regulation of signaling pathways involved in the control of many physiological functions is carried out via the heterotrimeric G protein-coupled receptors (GPCR). The search of effective and selective regulators of GPCR and intracellular signaling cascades coupled with them is one of the important problems of modern fundamental and clinical medicine. Recently data suggest that synthetic peptides and their derivatives, structurally corresponding to the intracellular and transmembrane regions of GPCR, can interact with high efficiency and selectivity with homologous receptors and influence, thus, the functional activity of intracellular signaling cascades and fundamental cellular processes controlled by them. GPCR-peptides are active in both in vitro and in vivo. They regulate hematopoiesis, angiogenesis and cell proliferation, inhibit tumor growth and metastasis, and prevent the inflammatory diseases and septic shock. These data show greatest prospects in the development of the new generations of drugs based on GPCR-derived peptides, capable of regulating the important functions of the organism.

scholarly journals Regulators of G protein Signaling (RGS) proteins (version 2020.4) in the IUPHAR/BPS Guide to Pharmacology Database

2020 ◽  
Vol 2020 (4) ◽  
Author(s):  
Katelin E. Ahlers-Dannen ◽  
Mohammed Alqinyah ◽  
Christopher Bodle ◽  
Josephine Bou Dagher ◽  
Bandana Chakravarti ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
Signaling Cascades ◽  
G Protein Signaling ◽  
Rgs Proteins ◽  
Protein Signaling ◽  
Heterotrimeric G Proteins ◽  
Gtp Hydrolysis ◽  
Rgs Domain ◽  
G Protein Coupled

Regulator of G protein Signaling, or RGS, proteins serve an important regulatory role in signaling mediated by G protein-coupled receptors (GPCRs). They all share a common RGS domain that directly interacts with active, GTP-bound Gα subunits of heterotrimeric G proteins. RGS proteins stabilize the transition state for GTP hydrolysis on Gα and thus induce a conformational change in the Gα subunit that accelerates GTP hydrolysis, thereby effectively turning off signaling cascades mediated by GPCRs. This GTPase accelerating protein (GAP) activity is the canonical mechanism of action for RGS proteins, although many also possess additional functions and domains. RGS proteins are divided into four families, R4, R7, R12 and RZ based on sequence homology, domain structure as well as specificity towards Gα subunits. For reviews on RGS proteins and their potential as therapeutic targets, see e.g. [160, 377, 411, 415, 416, 512, 519, 312, 6].

scholarly journals Aromatic D-amino acids act as chemoattractant factors for human leukocytes through a G protein-coupled receptor, GPR109B

2009 ◽  
Vol 106 (10) ◽  
pp. 3930-3934 ◽  
Author(s):  
Y. Irukayama-Tomobe ◽  
H. Tanaka ◽  
T. Yokomizo ◽  
T. Hashidate-Yoshida ◽  
M. Yanagisawa ◽  
...  
Keyword(s):  
Amino Acids ◽  
G Protein ◽  
G Protein Coupled Receptor ◽  
Human Leukocytes ◽  
G Protein Coupled

scholarly journals Human BAG-1 Proteins Bind to the Cellular Stress Response Protein GADD34 and Interfere with GADD34 Functions

2003 ◽  
Vol 23 (10) ◽  
pp. 3477-3486 ◽  
Author(s):  
Wesley J. Hung ◽  
Rachel S. Roberson ◽  
Jaime Taft ◽  
Daniel Y. Wu
Keyword(s):  
Stress Response ◽  
Cellular Stress ◽  
Cellular Stress Response ◽  
Initiation Factor ◽  
Protein Partners ◽  
Additional Protein ◽  
Sw480 Cells ◽  
Functional Mechanisms ◽  
Negative Growth

ABSTRACT The cellular stress response protein GADD34 mediates growth arrest and apoptosis in response to DNA damage, negative growth signals, and protein malfolding. GADD34 binds to protein phosphatase PP1 and can attenuate the translational elongation of key transcriptional factors through dephosphorylation of eukaryotic initiation factor 2α (eIF2α). Recently, we reported the involvement of human SNF5/INI1 (hSNF5/INI1) protein in the functions of GADD34 and showed that hSNF5/INI1 binds GADD34 and stimulates the bound PP1 phosphatase activity. To better understand the regulatory and functional mechanisms of GADD34, we undertook a yeast two-hybrid screen with full-length GADD34 as bait in order to identify additional protein partners of GADD34. We report here that human cochaperone protein BAG-1 interacts with GADD34 in vitro and in SW480 cells treated with the proteasome inhibitor z-LLL-B to induce apoptosis. Two other proteins, Hsp70/Hsc70 and PP1, associate reversibly with the GADD34-BAG-1 complex, and their dissociation is promoted by ATP. BAG-1 negatively modulates GADD34-bound PP1 activity, and the expression of BAG-1 isoforms can also mask GADD34-mediated inhibition of colony formation and suppression of transcription. Our findings suggest that BAG-1 may function to suppress the GADD34-mediated cellular stress response and support a role for BAG-1 in the survival of cells undergoing stress.

scholarly journals Nuclear GPCRs in cardiomyocytes: an insider's view of β-adrenergic receptor signaling

2011 ◽  
Vol 301 (5) ◽  
pp. H1754-H1764 ◽  
Author(s):  
George Vaniotis ◽  
Bruce G. Allen ◽  
Terence E. Hébert
Keyword(s):  
Subcellular Localization ◽  
G Protein ◽  
G Proteins ◽  
Adrenergic Receptor ◽  
Physiological State ◽  
Signaling Cascades ◽  
Special Focus ◽  
The Novel ◽  
Receptor Signaling ◽  
G Protein Coupled

In recent years, we have come to appreciate the complexity of G protein-coupled receptor signaling in general and β-adrenergic receptor (β-AR) signaling in particular. Starting originally from three β-AR subtypes expressed in cardiomyocytes with relatively simple, linear signaling cascades, it is now clear that there are large receptor-based networks which provide a rich and diverse set of responses depending on their complement of signaling partners and the physiological state. More recently, it has become clear that subcellular localization of these signaling complexes also enriches the diversity of phenotypic outcomes. Here, we review our understanding of the signaling repertoire controlled by nuclear β-AR subtypes as well our understanding of the novel roles for G proteins themselves in the nucleus, with a special focus, where possible, on their effects in cardiomyocytes. Finally, we discuss the potential pathological implications of alterations in nuclear β-AR signaling.

scholarly journals Modelo molecular teórico del receptor serotoninérgico 5HT2A acoplado a proteína G

2012 ◽  
Vol 17 (2) ◽  
pp. 119
Author(s):  
Rafael Eduardo Malagón Bernal ◽  
Manuel Alejandro Fernández Navas ◽  
Orlando Emilio Acevedo Sarmiento
Keyword(s):  
Theoretical Model ◽  
G Protein ◽  
Tertiary Structure ◽  
Homo Sapiens ◽  
Molecular Model ◽  
Ramachandran Plot ◽  
Bovine Rhodopsin ◽  
Protein Receptor ◽  
G Protein Coupled ◽  
Hydrophobicity Profile

<strong>Objective</strong> Build a theoretical molecular model of the tertiary structure of the Homo sapiens 5HT2A receptor from experimentally obtained structures as templates. <strong>Materials</strong> <strong>and methods</strong> In the construction of the theoretical model we considered the protocol established by Ballesteros and Weinstein for the construction of the G-protein coupled receptor, by the alignment of the amino acid sequence, hydrophobicity profiles, refinement of loops by spatial restrictions and energy minimization with the force field OPLS_2005. <strong>Results</strong> The resulting model was validated by the Ramachandran plot with 91.7% of amino acids within the limits set for angles phi and psi and a RMSD of 0.95 Å with respect to bovine rhodopsin. <strong>Conclusions</strong> We obtained a validated theoretical model useful in studies of ligand-receptor docking.<br /><strong>Key words</strong>: G protein receptor, hydrophobicity profile, Ramachandran plot, orthosteric site, molecular modelling.

scholarly journals A specific amino acid motif of HLA-DRB1 mediates risk and interacts with smoking history in Parkinson’s disease

2019 ◽  
Vol 116 (15) ◽  
pp. 7419-7424 ◽  
Author(s):  
Jill A. Hollenbach ◽  
Paul J. Norman ◽  
Lisa E. Creary ◽  
Vincent Damotte ◽  
Gonzalo Montero-Martin ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Amino Acids ◽  
Parkinson's Disease ◽  
Confidence Interval ◽  
Odds Ratio ◽  
Molecular Model ◽  
Peptide Binding ◽  
Smoking History ◽  
Disease Predisposition ◽  
History Of

Parkinson’s disease (PD) is a neurodegenerative disease in which genetic risk has been mapped to HLA, but precise allelic associations have been difficult to infer due to limitations in genotyping methodology. Mapping PD risk at highest possible resolution, we performed sequencing of 11 HLA genes in 1,597 PD cases and 1,606 controls. We found that susceptibility to PD can be explained by a specific combination of amino acids at positions 70–74 on the HLA-DRB1 molecule. Previously identified as the primary risk factor in rheumatoid arthritis and referred to as the “shared epitope” (SE), the residues Q/R-K/R-R-A-A at positions 70–74 in combination with valine at position 11 (11-V) is highly protective in PD, while risk is attributable to the identical epitope in the absence of 11-V. Notably, these effects are modified by history of cigarette smoking, with a strong protective effect mediated by a positive history of smoking in combination with the SE and 11-V (P = 10−4; odds ratio, 0.51; 95% confidence interval, 0.36–0.72) and risk attributable to never smoking in combination with the SE without 11-V (P = 0.01; odds ratio, 1.51; 95% confidence interval, 1.08–2.12). The association of specific combinations of amino acids that participate in critical peptide-binding pockets of the HLA class II molecule implicates antigen presentation in PD pathogenesis and provides further support for genetic control of neuroinflammation in disease. The interaction of HLA-DRB1 with smoking history in disease predisposition, along with predicted patterns of peptide binding to HLA, provide a molecular model that explains the unique epidemiology of smoking in PD.

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