scholarly journals Activation of Gαq sequesters specific transcripts into Ago2 particles

2021 ◽  
Author(s):  
Lela Jackson ◽  
Alison Poussaint ◽  
Suzanne Scarlata
Keyword(s):  
Protein Composition ◽  
Atp Synthesis ◽  
Stress Granules ◽  
Protein Signaling ◽  
Secretory Function ◽  
Signaling System ◽  
Chromogranin B ◽  
Mrna Transcripts ◽  
Specific Proteins ◽  
Stress Activation

Abstract Hormones and neurotransmitters can activate the Gαq / phospholipase Cβ1 (PLCβ1) signaling system eliciting cellular calcium responses. PLCβ1 also prevents the aggregation of ribosomal and RNA proteins into stress granules, which are halted translation complexes that form in response to cellular stress. Activation of Gαq promotes PLCβ1association releasing bound proteins and promoting the formation of stress granules. However, the cellular impact of stress granules formed from routine Gαq protein signaling is unknown. Here, we have characterized Ago2 stress granules formed in response to Gαq activation in a neuronal-like cell line. We find these stress granule have a distinct protein composition, and unlike stress granules formed under heat stress, contain only two mRNA transcripts, chromogranin B, which is involved in secretory function, and ATP synthase 5f1b, which is required for ATP synthesis. Our studies show an unexpected pathway where Gαq/PLCβ regulates the translation of specific proteins.

scholarly journals Lessons from Photoreceptors: Turning Off G-Protein Signaling in Living Cells

Physiology ◽  
2010 ◽  
Vol 25 (2) ◽  
pp. 72-84 ◽  
Author(s):  
Marie E. Burns ◽  
Edward N. Pugh
Keyword(s):  
G Protein ◽  
Living Cells ◽  
G Protein Signaling ◽  
Protein Signaling ◽  
Signaling System ◽  
Signaling Systems ◽  
Recent Advances ◽  
Retinal Rods

Phototransduction in retinal rods is one of the most extensively studied G-protein signaling systems. In recent years, our understanding of the biochemical steps that regulate the deactivation of the rod's response to light has greatly improved. Here, we summarize recent advances and highlight some of the remaining puzzles in this model signaling system.

scholarly journals Age and SPARC Change the Extracellular Matrix Composition of the Left Ventricle

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Lisandra E. de Castro Brás ◽  
Hiroe Toba ◽  
Catalin F. Baicu ◽  
Michael R. Zile ◽  
Susan T. Weintraub ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Left Ventricle ◽  
Protein Composition ◽  
Extracellular Proteins ◽  
Matrix Composition ◽  
Matricellular Protein ◽  
Middle Aged ◽  
Lv Dysfunction ◽  
Collagen Iii ◽  
Specific Proteins

Secreted protein acidic and rich in cysteine (SPARC), a collagen-binding matricellular protein, has been implicated in procollagen processing and deposition. The aim of this study was to investigate age- and SPARC-dependent changes in protein composition of the cardiac extracellular matrix (ECM). We studied 6 groups of mice (n=4/group): young (4-5 months old), middle-aged (11-12 m.o.), and old (18–29 m.o.) C57BL/6J wild type (WT) and SPARC null. The left ventricle (LV) was decellularized to enrich for ECM proteins. Protein extracts were separated by SDS-PAGE, digested in-gel, and analyzed by HPLC-ESI-MS/MS. Relative quantification was performed by spectral counting, and changes in specific proteins were validated by immunoblotting. We identified 321 proteins, of which 44 proteins were extracellular proteins. Of these proteins, collagen III levels were lower in the old null mice compared to WT, suggestive of a role for SPARC in collagen deposition. Additionally, fibrillin showed a significant increase in the null middle-aged group, suggestive of increased microfibril deposition in the absence of SPARC. Collagen VI increased with age in both genotypes (>3-fold), while collagen IV showed increased age-associated levels only in the WT animals (4-fold,P<0.05). These changes may explain the previously reported age-associated increases in LV stiffness. In summary, our data suggest SPARC is a possible therapeutic target for aging induced LV dysfunction.

scholarly journals Isolation and preliminary characterization of the major membrane boundaries of the endocytic pathway in lymphocytes.

1990 ◽  
Vol 111 (5) ◽  
pp. 1811-1823 ◽  
Author(s):  
B D Beaumelle ◽  
A Gibson ◽  
C R Hopkins
Keyword(s):  
Plasma Membrane ◽  
Protein Composition ◽  
Endocytic Pathway ◽  
Coated Pits ◽  
Selective Labeling ◽  
Specific Proteins ◽  
T Lymphoma ◽  
Cellular Compartments ◽  
Density Shift

Plasma membrane, coated pits, endosomes, and lysosomes were isolated from a mouse T lymphoma cell line using a density shift protocol in which these compartments were selectively loaded with gold conjugates. The plasma membrane was prepared after selective labeling for 1 h at 2 degrees C with gold-ricin and gave a yield of 40% according to enzymatic and antigenic markers. Endosomes were obtained by loading the cells for 2 h at 22 degrees C with gold complexed to an antimouse transferrin receptor mAb. Coated pits were isolated using a similar procedure, but after an incubation at 10 degrees C, which allowed deep invagination of the pits but prevented internalization. The yield (calculated using the recovery of [125I]transferrin) was 32% for endosomes and 10% for coated pits. Finally lysosomes were prepared by loading the cells for 18 h at 37 degrees C with gold low density lipoproteins (LDLs) followed by a 3-h chase at 37 degrees C with LDL alone. The final lysosome yield (based on the recovery of lysosomal enzymes) was 16%. Studies of the protein composition of these cellular compartments on two-dimensional gels showed that while some major proteins are present throughout the pathway, specific proteins can be identified in each of the isolated fractions. The greatest change in the pattern of protein constituents seen along the pathway was between endosomal and lysosomal preparations.

scholarly journals Suppression of Virulence of Toxigenic Vibrio cholerae by Anethole through the Cyclic AMP (cAMP)-cAMP Receptor Protein Signaling System

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0137529 ◽  
Author(s):  
M. Shamim Hasan Zahid ◽  
Sharda Prasad Awasthi ◽  
Masahiro Asakura ◽  
Shruti Chatterjee ◽  
Atsushi Hinenoya ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Vibrio Cholerae ◽  
Receptor Protein ◽  
Protein Signaling ◽  
Camp Receptor Protein ◽  
Signaling System ◽  
Camp Receptor

scholarly journals P bodies promote stress granule assembly in Saccharomyces cerevisiae

2008 ◽  
Vol 183 (3) ◽  
pp. 441-455 ◽  
Author(s):  
J. Ross Buchan ◽  
Denise Muhlrad ◽  
Roy Parker
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mammalian Cells ◽  
Protein Composition ◽  
Stress Granules ◽  
Glucose Deprivation ◽  
Stress Granule ◽  
Granule Formation ◽  
P Bodies ◽  
Rna Granules ◽  
Kinetics Of

Recent results indicate that nontranslating mRNAs in eukaryotic cells exist in distinct biochemical states that accumulate in P bodies and stress granules, although the nature of interactions between these particles is unknown. We demonstrate in Saccharomyces cerevisiae that RNA granules with similar protein composition and assembly mechanisms as mammalian stress granules form during glucose deprivation. Stress granule assembly is dependent on P-body formation, whereas P-body assembly is independent of stress granule formation. This suggests that stress granules primarily form from mRNPs in preexisting P bodies, which is also supported by the kinetics of P-body and stress granule formation both in yeast and mammalian cells. These observations argue that P bodies are important sites for decisions of mRNA fate and that stress granules, at least in yeast, primarily represent pools of mRNAs stalled in the process of reentry into translation from P bodies.

scholarly journals A Quantitative Proteome Map of the Human Body

2019 ◽  
Author(s):  
Lihua Jiang ◽  
Meng Wang ◽  
Shin Lin ◽  
Ruiqi Jian ◽  
Xiao Li ◽  
...  
Keyword(s):  
Protein Detection ◽  
Integrated Analysis ◽  
Protein Signaling ◽  
Transcriptome Data ◽  
Tissue Specific ◽  
Protein Levels ◽  
Metabolism Regulation ◽  
Regulatory Processes ◽  
Specific Proteins ◽  
Normal Human

AbstractDetermining protein levels in each tissue and how they compare with RNA levels is important for understanding human biology and disease as well as regulatory processes that control protein levels. We quantified the relative protein levels from 12,627 genes across 32 normal human tissue types prepared by the GTEx project. Known and new tissue specific or enriched proteins (5,499) were identified and compared to transcriptome data. Many ubiquitous transcripts are found to encode highly tissue specific proteins. Discordance in the sites of RNA expression and protein detection also revealed potential sites of synthesis and action of protein signaling molecules. Overall, these results provide an extraordinary resource, and demonstrate that understanding protein levels can provide insights into metabolism, regulation, secretome, and human diseases.SummaryQuantitative proteome study of 32 human tissues and integrated analysis with transcriptome data revealed that understanding protein levels could provide in-depth knowledge to post transcriptional or translational regulations, human metabolism, secretome, and diseases.

scholarly journals Human U4/U6.U5 and U4atac/U6atac.U5 Tri-snRNPs Exhibit Similar Protein Compositions

2002 ◽  
Vol 22 (10) ◽  
pp. 3219-3229 ◽  
Author(s):  
Claudia Schneider ◽  
Cindy L. Will ◽  
Olga V. Makarova ◽  
Evgeny M. Makarov ◽  
Reinhard Lührmann
Keyword(s):  
Comparative Analysis ◽  
Common Ancestor ◽  
Sequence Similarity ◽  
Evolutionary Model ◽  
Protein Composition ◽  
Significant Sequence Similarity ◽  
Similar Protein ◽  
Specific Proteins

ABSTRACT In the U12-dependent spliceosome, the U4atac/U6atac snRNP represents the functional analogue of the major U4/U6 snRNP. Little information is available presently regarding the protein composition of the former snRNP and its association with other snRNPs. In this report we show that human U4atac/U6atac di-snRNPs associate with U5 snRNPs to form a 25S U4atac/U6atac.U5 trimeric particle. Comparative analysis of minor and major tri-snRNPs by using immunoprecipitation experiments revealed that their protein compositions are very similar, if not identical. Not only U5-specific proteins but, surprisingly, all tested U4/U6- and major tri-snRNP-specific proteins were detected in the minor tri-snRNP complex. Significantly, the major tri-snRNP-specific proteins 65K and 110K, which are required for integration of the major tri-snRNP into the U2-dependent spliceosome, were among those proteins detected in the minor tri-snRNP, raising an interesting question as to how the specificity of addition of tri-snRNP to the corresponding spliceosome is maintained. Moreover, immunodepletion studies demonstrated that the U4/U6-specific 61K protein, which is involved in the formation of major tri-snRNPs, is essential for the association of the U4atac/U6atac di-snRNP with U5 to form the U4atac/U6atac.U5 tri-snRNP. Subsequent immunoprecipitation studies demonstrated that those proteins detected in the minor tri-snRNP complex are also incorporated into U12-dependent spliceosomes. This remarkable conservation of polypeptides between minor and major spliceosomes, coupled with the absence of significant sequence similarity between the functionally analogous snRNAs, supports an evolutionary model in which most major and minor spliceosomal proteins, but not snRNAs, are derived from a common ancestor.

Simulation of the effects of moderate stimulation/inhibition of the β1-adrenergic signaling system and its components in mouse ventricular myocytes

2016 ◽  
Vol 310 (11) ◽  
pp. C844-C856 ◽  
Author(s):  
Mark Grinshpon ◽  
Vladimir E. Bondarenko
Keyword(s):  
Mathematical Model ◽  
Action Potential ◽  
Action Potential Duration ◽  
Ventricular Myocytes ◽  
Cardiac Cells ◽  
Protein Signaling ◽  
Signaling System ◽  
Adrenergic Signaling ◽  
Signaling Systems ◽  
Stimulation Of

The β1-adrenergic signaling system is one of the most important protein signaling systems in cardiac cells. It regulates cardiac action potential duration, intracellular Ca2+concentration ([Ca2+]i) transients, and contraction force. In this paper, a comprehensive experimentally based mathematical model of the β1-adrenergic signaling system for mouse ventricular myocytes is explored to simulate the effects of moderate stimulations of β1-adrenergic receptors (β1-ARs) on the action potential, Ca2+and Na+dynamics, as well as the effects of inhibition of protein kinase A (PKA) and phosphodiesterase of type 4 (PDE4). Simulation results show that the action potential prolongations reach saturating values at relatively small concentrations of isoproterenol (∼0.01 μM), while the [Ca2+]itransient amplitude saturates at significantly larger concentrations (∼0.1–1.0 μM). The differences in the response of Ca2+and Na+fluxes to moderate stimulation of β1-ARs are also observed. Sensitivity analysis of the mathematical model is performed and the model limitations are discussed. The investigated model reproduces most of the experimentally observed effects of moderate stimulation of β1-ARs, PKA, and PDE4 inhibition on the L-type Ca2+current, [Ca2+]itransients, and the sarcoplasmic reticulum Ca2+load and makes testable predictions for the action potential duration and [Ca2+]itransients as functions of isoproterenol concentration.

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