scholarly journals Phosphorylation dynamics in a flg22-induced, G-protein dependent network in Arabidopsis thaliana

2021 ◽  
Author(s):  
Justin M Watkins ◽  
Natalie M Clark ◽  
Gaoyuan Song ◽  
Celio Cabral Oliveira ◽  
Bharat Mishra ◽  
...  
Keyword(s):  
G Protein ◽  
Protein Complex ◽  
Protein Abundance ◽  
Dependent Manner ◽  
Arabidopsis Root ◽  
Protein Interactome ◽  
Massive Change ◽  
Induced Changes ◽  
Cell Proteome ◽  
G Protein Coupled

flg22 is recognized by the plant cell as a signal indicating that bacteria are present. Here we show a rapid and massive change in protein abundance and phosphorylation state of the Arabidopsis root cell proteome in wildtype and a mutant deficient in G-protein coupled signaling. Many of the flg22-induced changes fall on proteins comprising the G protein interactome and on highly populated hubs of the immunity network. Approximately 95% of the phosphorylation changes in the G-protein interactome depend on a functional G protein complex; some on proteins in the G protein interactome. One of these is ATB?, an interactor to REGULATOR OF G SIGNALING 1 protein (AtRGS1), a 7-transmembrane spanning modulator of the nucleotide-binding state of the core G protein complex. A null mutation of ATB? confers basal endocytosis of AtRGS1. AtRGS1 level is lower in the atb? mutant in a proteasome-dependent manner. We propose that phosphorylation-dependent endocytosis of AtRGS1 is part of the mechanism to degrade AtRGS1 thus sustaining activation of the G protein complex required for regulation of system dynamics in innate immunity.

scholarly journals Phosphorylation dynamics in a flg22 induced, heterotrimeric G protein dependent signaling network in Arabidopsis thaliana reveals a candidate PP2A phosphatase involved in AtRGS1 trafficking

2021 ◽  
Author(s):  
Justin Michael Watkins ◽  
Alan M. Jones ◽  
Justin Walley ◽  
Natalie M Clark ◽  
Daisuke Urano ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
G Protein ◽  
Protein Complex ◽  
Protein A ◽  
Mitogen Activated Protein Kinase ◽  
Central Component ◽  
Dependent Manner ◽  
Heterotrimeric G Protein ◽  
Protein Interactome ◽  
Mitogen Activated Protein

flg22 is a 22 amino peptide released from bacterial flagellin a Microbe Associated Molecular 51 Pattern ( that is recognized by the plant cell as a signal indicating that bacteria are present. On its own, flg22 initiates a rapid increase in cytoplasmic calcium, extracellular reactive oxygen species, and activation of a Mitogen Activated Protein Kinase (cascade all of which are activated within 15 minutes after the cell perceives flg22. Here we show a massive change in protein abundance and phosphorylation state of the Arabidopsis root cell proteome within this 15 minute duration in wildtype and a mutant deficient in G protein coupled signaling Integration of phosphoproteome with protein protein interactome data followed by network topology analyses discovered that many of the flg22 induced phosphoproteome changes fall on proteins that comprise the G protein interactome and on the most highly populated hubs of the immunity network approximately 95% of the phosphorylation changes in the G protein interactome depend on a functional heterotrimeric G protein complex some occur on proteins that interact directly with components of G coupled signal transduction. One of these is ATBα, a substrate recognition sub-unit of the PP2A Ser/Thr phosphatase and an interactor to Arabidopsis thaliana REGULATOR OF G SIGNALING 1 protein (a 7 transmembrane spanning modulator of the nucleotide binding state of the core G protein complex. AtRGS1 is phosphorylated by BAK1, a component of the flg22 receptor, to initiate AtRGS1 endocytosis. A null mutation of ATB α confer s high 67 basal endocytosis of AtRGS1 suggesting sustained phosphorylated status. Loss of ATB α confers 68 trait s associated with loss of AtRGS1. Because the basal level of AtRGS1 is lower in the atbα null mutant in a proteasome dependent manner we propose that phosphorylation dependent endocytosis of AtRGS1 is part of a mechanism to degrade AtRGS1 which then sustains activation of the 71 G protein complex Thus, the role of ATB α is now established as a central component of phosphorylation dependent regulation of system dynamics in innate immunity

scholarly journals Possible Relevance of Receptor-Receptor Interactions between Viral- and Host-Coded Receptors for Viral-Induced Disease

2007 ◽  
Vol 7 ◽  
pp. 1073-1081 ◽  
Author(s):  
Luigi F. Agnati ◽  
Giuseppina Leo ◽  
Susanna Genedani ◽  
Diego Guidolin ◽  
Nicola Andreoli ◽  
...  
Keyword(s):  
Immune System ◽  
G Protein ◽  
Cell Metabolism ◽  
G Protein Coupled Receptors ◽  
Host Cells ◽  
Receptor Function ◽  
Viral Receptor ◽  
Receptor Interactions ◽  
Induced Changes ◽  
G Protein Coupled

It has been demonstrated that some viruses, such as the cytomegalovirus, code for G-protein coupled receptors not only to elude the immune system, but also to redirect cellular signaling in the receptor networks of the host cells. In view of the existence of receptor-receptor interactions, the hypothesis is introduced that these viral-coded receptors not only operate as constitutively active monomers, but also can affect other receptor function by interacting with receptors of the host cell. Furthermore, it is suggested that viruses could also insert not single receptors (monomers), but clusters of receptors (receptor mosaics), altering the cell metabolism in a profound way. The prevention of viral receptor-induced changes in host receptor networks may give rise to novel antiviral drugs that counteract viral-induced disease.

scholarly journals Substrate-Induced Changes in the Dynamics of Rhodopsin Kinase (G Protein-Coupled Receptor Kinase 1)

Biochemistry ◽  
2012 ◽  
Vol 51 (16) ◽  
pp. 3404-3411 ◽  
Author(s):  
Tivadar Orban ◽  
Chih-chin Huang ◽  
Kristoff T. Homan ◽  
Beata Jastrzebska ◽  
John J. G. Tesmer ◽  
...  
Keyword(s):  
G Protein ◽  
Receptor Kinase ◽  
G Protein Coupled Receptor ◽  
Rhodopsin Kinase ◽  
Induced Changes ◽  
G Protein Coupled

Arrestin-2 Regulates Akt Activation by G Protein-Coupled Receptors in Platelets.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1525-1525
Author(s):  
Dongjun Li ◽  
Donna S. Woulfe
Keyword(s):  
G Protein ◽  
Genetic Manipulation ◽  
Embryonic Stem ◽  
Phosphatidyl Inositol ◽  
G Protein Coupled Receptors ◽  
Resting Cells ◽  
Dependent Manner ◽  
Akt Phosphorylation ◽  
Receptor Sites ◽  
G Protein Coupled

Abstract Arrestins have been shown to play important roles in G Protein-Coupled Receptor (GPCR) function in many cells, but their roles in platelets remain uncharacterized. While the classical role of arrestins is considered to be the internalization and desensitization of GPCRs, more recent studies suggest that arrestins can serve as scaffolds to recruit phosphatidyl inositol-3 kinases (PI3K)s to Gq-coupled receptors and promote PI3K-dependent signaling. Thrombin stimulates the PI3K-dependent activation of Akt in platelets in a Gq-dependent manner. Therefore, we sought to determine whether arrestins are involved in the PI3K-dependent activation of Akt in platelets. Comparative immunoblots show that of the two non-visual mammalian arrestins, only one, arrestin-2 (β-arrestin-1), is expressed in human and mouse platelets. Immunoprecipitation of arrestin-2 or p85-PI3K from platelet lysates demonstrated that arrestin-2 associates with the p85 subunit of PI3Ka/b in thrombin or ADP-stimulated platelets, but not resting cells. The association can be inhibited by inhibitors of the P2Y12 receptor for ADP, but not by P2Y1 inhibitors. p85-arrestin association is also blocked by inhibitors of src family kinases, as is Akt phosphorylation. To determine whether src family members were part of the p85-arrestin complexes, immunoblots were re-probed with antibodies to src, lyn and fyn. The results show that Lyn is incorporated into thrombin-stimulated arrestin complexes in a P2Y12-dependent manner. To determine whether arrestin-2 is important for Akt phosphorylation in platelets, megakaryocytes differentiated in culture from mouse embryonic stem cells were used as models of platelet signaling, since these cells are amenable to genetic manipulation. Arrestin-2 was inhibited in the cultured megakaryocytes using a siRNA approach, then cells were stimulated with thrombin and Akt phosphorylation was assessed by immunoblotting. Arrestin-2 expression in the cultured megakaryocytes treated with arrestin-2 specific siRNA was suppressed by an average of 53% compared to cells treated with scrambled siRNA, while thrombin-stimulated Akt phosphorylation was suppressed by 98% compared to scrambled siRNA-treated control cells (n=3 experiments, difference is significant, p=.01, unpaired student’s t-test). In conclusion, the results show that arrestin-2, lyn and PI3Kform a tri-molecular complex following stimulation of platelets with ADP or thrombin. Formation of arrestin complexes at activated receptor sites is important for the localized recruitment and src-dependent activation of p85-PI3K, thus promoting activation of Akt by G protein-coupled receptors.

scholarly journals Increase of Anteroventral Periventricular Kisspeptin Neurons and Generation of E2-Induced LH-Surge System in Male Rats Exposed Perinatally to Environmental Dose of Bisphenol-A

Endocrinology ◽  
2011 ◽  
Vol 152 (4) ◽  
pp. 1562-1571 ◽  
Author(s):  
Yinyang Bai ◽  
Fei Chang ◽  
Rong Zhou ◽  
Peng-Peng Jin ◽  
Hirokazu Matsumoto ◽  
...  
Keyword(s):  
Bisphenol A ◽  
G Protein ◽  
Female Rats ◽  
Male Rats ◽  
Perinatal Exposure ◽  
Dependent Manner ◽  
G Protein Coupled Receptor ◽  
Control Male ◽  
Lh Surge ◽  
G Protein Coupled

Abstract Perinatal exposure to environmental levels of bisphenol-A (BPA) impairs sexually dimorphic behaviors in rodents. Kisspeptin neurons in anteroventral periventricular nucleus (AVPV), which plays an important role in the activation of GnRH neurons and the initiation of LH-surge, have been suggested to be sexual dimorphism in rats. This study focused on exploring the influence of a perinatal exposure to an environmental dose of BPA on the development and maturation of male AVPV kisspeptin neurons and hypothalamus-pituitary-gonadal axis. Female rats were injected sc with 2 μg BPA/kg·d from gestation d 10 through lactation d 7. Anatomical and functional changes in AVPV kisspeptin neurons and hypothalamus-pituitary-gonadal axis were examined in prepubertal, pubertal, and adult male rats exposed perinatally to BPA (BPA-rats). Here, we show that in postnatal d (PND)30/50/90 BPA-rats, the number of AVPV kisspeptin-immunoreactive cells was persistently increased in comparison with age-matched control male rats. The number of GnRH-immunoreactive cells in PND30 BPA-rats declined approximately 40% compared with control male rats, whereas that in PND50/90 BPA-rats was increased in a G protein-coupled receptor 54-dependent manner. Estradiol could induce a stable LH-surge in PND90 BPA-rats and control female rats, which was sensitive to the G protein-coupled receptor 54 inhibitor. In PND30/50 BPA-rats, plasma level of LH was higher, but the level of testosterone was lower than control male rats. These findings provide evidence that perinatal exposure to an environmental dose of BPA causes a sustained increase in AVPV kisspeptin neurons in male rats, leading to the generation of estradiol-induced LH-surge system.

scholarly journals Sphingosine 1-phosphate receptor 2 antagonist JTE-013 increases the excitability of sensory neurons independently of the receptor

2012 ◽  
Vol 108 (5) ◽  
pp. 1473-1483 ◽  
Author(s):  
Chao Li ◽  
Xian Xuan Chi ◽  
Wenrui Xie ◽  
J. A. Strong ◽  
J.-M. Zhang ◽  
...  
Keyword(s):  
G Protein ◽  
Sensory Neurons ◽  
Neuronal Excitability ◽  
Small Diameter ◽  
G Protein Coupled Receptors ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Sphingosine 1 Phosphate ◽  
G Protein Coupled

Previously we demonstrated that sphingosine 1-phosphate receptor 1 (S1PR1) played a prominent, but not exclusive, role in enhancing the excitability of small-diameter sensory neurons, suggesting that other S1PRs can modulate neuronal excitability. To examine the potential role of S1PR2 in regulating neuronal excitability we used the established selective antagonist of S1PR2, JTE-013. Here we report that exposure to JTE-013 alone produced a significant increase in excitability in a time- and concentration-dependent manner in 70–80% of recorded neurons. Internal perfusion of sensory neurons with guanosine 5′- O-(2-thiodiphosphate) (GDP-β-S) via the recording pipette inhibited the sensitization produced by JTE-013 as well as prostaglandin E2. Pretreatment with pertussis toxin or the selective S1PR1 antagonist W146 blocked the sensitization produced by JTE-013. These results indicate that JTE-013 might act as an agonist at other G protein-coupled receptors. In neurons that were sensitized by JTE-013, single-cell RT-PCR studies demonstrated that these neurons did not express the mRNA for S1PR2. In behavioral studies, injection of JTE-013 into the rat's hindpaw produced a significant increase in the mechanical sensitivity in the ipsilateral, but not contralateral, paw. Injection of JTE-013 did not affect the withdrawal latency to thermal stimulation. Thus JTE-013 augments neuronal excitability independently of S1PR2 by unknown mechanisms that may involve activation of other G protein-coupled receptors such as S1PR1. Clearly, further studies are warranted to establish the causal nature of this increased sensitivity, and future studies of neuronal function using JTE-013 should be interpreted with caution.

scholarly journals Activation of Intracellular Signaling Pathways by the Murine Cytomegalovirus G Protein-Coupled Receptor M33 Occurs via PLC-β/PKC-Dependent and -Independent Mechanisms

2009 ◽  
Vol 83 (16) ◽  
pp. 8141-8152 ◽  
Author(s):  
Joseph D. Sherrill ◽  
Melissa P. Stropes ◽  
Olivia D. Schneider ◽  
Diana E. Koch ◽  
Fabiola M. Bittencourt ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Kinase ◽  
Signaling Pathways ◽  
G Protein ◽  
Intracellular Signaling ◽  
Murine Cytomegalovirus ◽  
Dependent Manner ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled

ABSTRACT The presence of numerous G protein-coupled receptor (GPCR) homologs within the herpesvirus genomes suggests an essential role for these genes in viral replication in the infected host. Such is the case for murine cytomegalovirus (MCMV), where deletion of the M33 GPCR or replacement of M33 with a signaling defective mutant has been shown to severely attenuate replication in vivo. In the present study we utilized a genetically altered version of M33 (termed R131A) in combination with pharmacological inhibitors to further characterize the mechanisms by which M33 activates downstream signaling pathways. This R131A mutant of M33 fails to support salivary gland replication in vivo and, as such, is an important tool that can be used to examine the signaling activities of M33. We show that M33 stimulates the transcription factor CREB via heterotrimeric Gq/11 proteins and not through promiscuous coupling of M33 to the Gs pathway. Using inhibitors of signaling molecules downstream of Gq/11, we demonstrate that M33 stimulates CREB transcriptional activity in a phospholipase C-β and protein kinase C (PKC)-dependent manner. Finally, utilizing wild-type and R131A versions of M33, we show that M33-mediated activation of other signaling nodes, including the mitogen-activated protein kinase family member p38α and transcription factor NF-κB, occurs in the absence of Gq/11 and PKC signaling. The results from the present study indicate that M33 utilizes multiple mechanisms to modulate intracellular signaling cascades and suggest that signaling through PLC-β and PKC plays a central role in MCMV pathogenesis in vivo.

Energy and metabolic sensing G protein–coupled receptors during lactation-induced changes in energy balance

2014 ◽  
Vol 48 ◽  
pp. 33-41 ◽  
Author(s):  
P. Friedrichs ◽  
B. Saremi ◽  
S. Winand ◽  
J. Rehage ◽  
S. Dänicke ◽  
...  
Keyword(s):  
Energy Balance ◽  
G Protein ◽  
G Protein Coupled Receptors ◽  
Metabolic Sensing ◽  
Induced Changes ◽  
G Protein Coupled

scholarly journals Activation of GPR39 With TC-G 1008 Attenuates Neuroinflammation Via SIRT1/PGC-1α/Nrf2 Pathway Post Neonatal Hypoxic-ischemic Injury in Rats

2021 ◽  
Author(s):  
Shucai Xie ◽  
Xili Jiang ◽  
Desislava Met Doycheva ◽  
Hui Shi ◽  
Peng Jin ◽  
...  
Keyword(s):  
G Protein ◽  
Sirtuin 1 ◽  
Neonatal Rat ◽  
Neurological Deficits ◽  
Dependent Manner ◽  
G Protein Coupled Receptor ◽  
Short Term ◽  
Nrf2 Pathway ◽  
G Protein Coupled

Abstract Background: Hypoxic-ischemic encephalopathy (HIE) is a severe anoxic brain injury that leads to premature mortality or long-term disabilities in infants. Neuroinflammation is a vital contributor to the pathogenic cascade post HIE and a mediator to secondary neuronal death. As a plasma membrane G-protein coupled receptor, GPR39, exhibits anti-inflammatory activity in several diseases. This study aimed to explore the neuroprotective function of GPR39 through inhibition of inflammation post hypoxic-ischemic (HI) injury and to elaborate the contribution of sirtuin 1(SIRT1)/ peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α)/ nuclear factor, erythroid 2 like 2(Nrf2) in G protein-coupled receptor 39 (GPR39)-mediated protection.Methods: A total of 206 10-day old Sprague Dawley rat pups were subjected to HIE or sham surgery. TC-G 1008 was administered intranasally at 1h, 25h, 49h, and 73h post HIE induction. SIRT1 inhibitor EX527, GPR39 CRISPR, and PGC-1α CRISPR were administered to elucidate the underlying mechanisms. Brain infarct area, short-term and long-term neurobehavioral tests, Nissl staining, western blot, and immunofluorescence staining were performed post HIE.Results: The expression of GPR39 and pathway-related proteins, SIRT1、PGC-1α and Nrf2 were increased in a time-dependent manner, peaking at 24 h or 48h post HIE. Intranasal administration of TC-G 1008 reduced the percent infarcted area and improved short-term and long-term neurological deficits. Moreover, TC-G 1008 treatment significantly increased the expression of SIRT1, PGC-1α, Nrf2, IL-6, IL-1β, and TNF-α. GPR39 CRISPR EX527 and PGC-1α CRISPR abolished GPR39’s neuroprotective effects post HIE.Conclusions:TC-G 1008 attenuated neuroinflammation in part via the SIRT1/PGC-1α/Nrf2 pathway in a neonatal rat model of HIE. TC-G 1008 may be a novel therapeutic target for treatment post neonatal HIE injury.

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