scholarly journals Expression profiling of the adhesion G protein-coupled receptor GPR133 (ADGRD1) in glioma subtypes

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Joshua D Frenster ◽  
Michael Kader ◽  
Scott Kamen ◽  
James Sun ◽  
Luis Chiriboga ◽  
...  
Keyword(s):  
Brain Tissue ◽  
G Protein ◽  
De Novo ◽  
Treatment Options ◽  
Wild Type ◽  
G Protein Coupled Receptor ◽  
Who Grade ◽  
Advanced Malignancy ◽  
G Protein Coupled ◽  
The Brain

Abstract Background Glioma is a family of primary brain malignancies with limited treatment options and in need of novel therapies. We previously demonstrated that the adhesion G protein-coupled receptor GPR133 (ADGRD1) is necessary for tumor growth in adult glioblastoma, the most advanced malignancy within the glioma family. However, the expression pattern of GPR133 in other types of adult glioma is unknown. Methods We used immunohistochemistry in tumor specimens and non-neoplastic cadaveric brain tissue to profile GPR133 expression in adult gliomas. Results We show that GPR133 expression increases as a function of WHO grade and peaks in glioblastoma, where all tumors ubiquitously express it. Importantly, GPR133 is expressed within the tumor bulk, as well as in the brain-infiltrating tumor margin. Furthermore, GPR133 is expressed in both isocitrate dehydrogenase (IDH) wild-type and mutant gliomas, albeit at higher levels in IDH wild-type tumors. Conclusion The fact that GPR133 is absent from non-neoplastic brain tissue but de novo expressed in glioma suggests that it may be exploited therapeutically.

scholarly journals The protective role of proton-sensing TDAG8 in the brain injury in a mouse ischemia reperfusion model

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Koichi Sato ◽  
Ayaka Tobo ◽  
Chihiro Mogi ◽  
Masayuki Tobo ◽  
Nobuhiro Yamane ◽  
...  
Keyword(s):  
Cerebral Infarction ◽  
G Protein ◽  
Morphological Changes ◽  
Ischemia Reperfusion ◽  
Protective Role ◽  
Cerebral Injury ◽  
G Protein Coupled Receptor ◽  
Dysfunctional Behavior ◽  
G Protein Coupled ◽  
The Brain

Abstract Extracellular acidification in the brain has been observed in ischemia; however, the physiological and pathophysiological implications of the pH reduction remain largely unknown. Here, we analyzed the roles of proton-sensing G protein-coupled receptors, including T-cell death-associated gene 8 (TDAG8), ovarian cancer G protein-coupled receptor 1 (OGR1), and G protein-coupled receptor 4 (GPR4) in a mouse ischemia reperfusion model. Cerebral infarction and dysfunctional behavior with transient middle cerebral artery occlusion (tMCAO) and subsequent reperfusion were exacerbated by the deficiency of TDAG8, whereas no significant effect was observed with the deficiency of OGR1 or GPR4. We confirmed that the pH of the predicted infarction region was 6.5. TDAG8 mRNA was observed in Iba1-positive microglia in the mouse brain. The tMCAO increased the mRNA expression of tumor necrosis factor-α in the ipsilateral cerebral hemisphere and evoked morphological changes in microglia in an evolving cerebral injury. These tMCAO-induced actions were significantly enhanced by the TDAG8 deficiency. Administration of minocycline, which is known to inhibit microglial activation, improved the cerebral infarction and dysfunctional behavior induced by tMCAO in the TDAG8-deficient mouse. Thus, acidic pH/TDAG8 protects against cerebral infarction caused by tMCAO, at least due to the mechanism involving the inhibition of microglial functions.

scholarly journals Dysfunction of G Protein-Coupled Receptor Kinases in Alzheimer’'s Disease

2010 ◽  
Vol 10 ◽  
pp. 1667-1678 ◽  
Author(s):  
William Z. Suo ◽  
Longxuan Li
Keyword(s):  
G Protein ◽  
Basal Forebrain ◽  
Brain Inflammation ◽  
G Protein Coupled Receptor ◽  
Amyloid Accumulation ◽  
Cognitive Levels ◽  
Receptor Kinases ◽  
Β Amyloid ◽  
G Protein Coupled ◽  
The Brain

Although mutations and variations of several genes have been identified to be involved in Alzheimer's disease (AD), the efforts towards understanding the pathogenic mechanisms of the disease still have a long journey to go. One such effort is to identify the signal transduction deficits, for which previous studies have suggested that the central problems appear to be at the interface between G proteins and their coupled receptors. G protein-coupled receptor kinases (GRKs) are a small family of serine/threonine protein kinases primarily acting at the “receptor-G protein interface””. Recent studies have indicated the possible involvement of GRK, primarily GRK2 and GRK5, dysfunction in the pathogenesis of AD. It seems that mild, soluble, β-amyloid accumulation can lead to a reduced membrane (functional) and an elevated cytosolic GRK2/5. The increased cytosolic GRK2 appears to be colocalized with damaged mitochondria and neurofibrillary tangles. Moreover, the total levels of GRK2, not only in the brain, but also in peripheral blood samples, are increased in a manner inversely correlated with the patient's cognitive levels. The deficiency of GRK5, on the other hand, impairs presynaptic M2 autoreceptor desensitization, which leads to a reduced acetylcholine release, axonal/synaptic degenerative changes, and associated amnestic, mild cognitive impairment. It also promotes an evil cycle to further increase Beta-amyloid accumulation and exaggerates brain inflammation, possibly even the basal forebrain cholinergic degeneration. Therefore, continuous efforts in this direction are necessary before translating the knowledge to any therapeutic strategies.

scholarly journals G protein–coupled receptor/arrestin3 modulation of the endocytic machinery

2002 ◽  
Vol 156 (4) ◽  
pp. 665-676 ◽  
Author(s):  
Francesca Santini ◽  
Ibragim Gaidarov ◽  
James H. Keen
Keyword(s):  
G Protein ◽  
Fluorescent Protein ◽  
De Novo ◽  
Membrane Skeleton ◽  
Live Cells ◽  
G Protein Coupled Receptor ◽  
Cortical Actin ◽  
Endocytic Machinery ◽  
Green Fluorescent ◽  
G Protein Coupled

Nonvisual arrestins (arr) modulate G protein–coupled receptor (GPCR) desensitization and internalization and bind to both clathrin (CL) and AP-2 components of the endocytic coated pit (CP). This raises the possibility that endocytosis of some GPCRs may be a consequence of arr-induced de novo CP formation. To directly test this hypothesis, we examined the behavior of green fluorescent protein (GFP)-arr3 in live cells expressing β2-adrenergic receptors and fluorescent CL. After agonist stimulation, the diffuse GFP-arr3 signal rapidly became punctate and colocalized virtually completely with preexisting CP spots, demonstrating that activated complexes accumulate in previously formed CPs rather than nucleating new CP formation. After arr3 recruitment, CP appeared larger: electron microscopy analysis revealed an increase in both CP number and in the occurrence of clustered CPs. Mutant arr3 proteins with impaired binding to CL or AP-2 displayed reduced recruitment to CPs, but were still capable of inducing CP clustering. In contrast, though constitutively present in CPs, the COOH-terminal moiety of arr3, which contains CP binding sites but lacks receptor binding, did not induce CP clustering. Together, these results indicate that recruitment of functional arr3–GPCR complexes to CP is necessary to induce clustering. Latrunculin B or 16°C blocked CP rearrangements without affecting arr3 recruitment to CP. These results and earlier studies suggest that discrete CP zones exist on cell surfaces, each capable of supporting adjacent CPs, and that the cortical actin membrane skeleton is intimately involved with both the maintenance of existing CPs and the generation of new structures.

scholarly journals Serine 129 phosphorylation of membrane-associated α-synuclein modulates dopamine transporter function in a G protein–coupled receptor kinase–dependent manner

2013 ◽  
Vol 24 (11) ◽  
pp. 1649-1660 ◽  
Author(s):  
Susumu Hara ◽  
Shigeki Arawaka ◽  
Hiroyasu Sato ◽  
Youhei Machiya ◽  
Can Cui ◽  
...  
Keyword(s):  
Cell Surface ◽  
G Protein ◽  
Dopamine Transporter ◽  
Surface Expression ◽  
Hek293 Cells ◽  
Cell Surface Expression ◽  
Receptor Kinase ◽  
Wild Type ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled

Most α-synuclein (α-syn) deposited in Lewy bodies, the pathological hallmark of Parkinson disease (PD), is phosphorylated at Ser-129. However, the physiological and pathological roles of this modification are unclear. Here we investigate the effects of Ser-129 phosphorylation on dopamine (DA) uptake in dopaminergic SH-SY5Y cells expressing α-syn. Subcellular fractionation of small interfering RNA (siRNA)–treated cells shows that G protein–coupled receptor kinase 3 (GRK3), GRK5, GRK6, and casein kinase 2 (CK2) contribute to Ser-129 phosphorylation of membrane-associated α-syn, whereas cytosolic α-syn is phosphorylated exclusively by CK2. Expression of wild-type α-syn increases DA uptake, and this effect is diminished by introducing the S129A mutation into α-syn. However, wild-type and S129A α-syn equally increase the cell surface expression of dopamine transporter (DAT) in SH-SY5Y cells and nonneuronal HEK293 cells. In addition, siRNA-mediated knockdown of GRK5 or GRK6 significantly attenuates DA uptake without altering DAT cell surface expression, whereas knockdown of CK2 has no effect on uptake. Taken together, our results demonstrate that membrane-associated α-syn enhances DA uptake capacity of DAT by GRKs-mediated Ser-129 phosphorylation, suggesting that α-syn modulates intracellular DA levels with no functional redundancy in Ser-129 phosphorylation between GRKs and CK2.

Transcriptional Activation of the Bradykinin Type 2 Receptor by the Tumor Suppressor P53.

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 719-719
Author(s):  
Samir S El-Dahr ◽  
Zubaida Saifudeen ◽  
Hong Du
Keyword(s):  
Tumor Suppressor ◽  
G Protein ◽  
Dominant Negative Mutant ◽  
Wild Type ◽  
G Protein Coupled Receptor ◽  
Water Excretion ◽  
Flanking Region ◽  
Wild Type P53 ◽  
G Protein Coupled

P145 The bradykinin type 2 receptor (BK2) is a developmentally regulated G protein-coupled receptor that mediates diverse actions such as vascular reactivity, salt and water excretion, inflammatory responses and cell growth. However, little is known regarding regulation of the BK2 gene. We report here that the rat BK2 receptor is transcriptionally regulated by the tumor suppressor protein p53. The 5’-flanking region of the rat BK2 gene contains two p53-like binding sites: a sequence at -70 bp (P1 site) that is conserved in the murine and human BK2 genes; and a sequence at -707 (P2) that is not. The P1 and P2 motifs bind specifically to p53, as assessed by gel mobility shift assays. Transient transfection into HeLa cells of a CAT reporter construct driven by 1.2-kb of the BK2 gene 5’-flanking region demonstrated that the BK2 promoter is dose-dependently activated by co-expression of wild-type p53. Co-expression of a dominant negative mutant p53 suppresses the activation of BK2 by wild-type p53. Promoter truncation localized the p53-responsive element to the region between -38 and -94 bp encompassing the p53-binding P1 sequence. Site-directed mutagenesis of the P1 site abolishes p53-mediated activation of BK2. Furthermore, p53-mediated activation of the BK2 promoter is augmented by the transcriptional co-activators, CBP/p300. Interestingly, removal of the P2 site by truncation or site-directed deletion amplifies p53-mediated activation of the BK2 promoter. These results demonstrate that the rat BK2 promoter is a target for p53-mediated activation and suggest a new physiological role for p53 in the regulation of G protein-coupled receptor gene expression.

scholarly journals The human cytomegalovirus G-protein coupled receptor US28 promotes latency by attenuating c-fos

2018 ◽  
Author(s):  
Benjamin A. Krishna ◽  
Monica S. Humby ◽  
William E. Miller ◽  
Christine M. O’Connor
Keyword(s):  
Host Cell ◽  
G Protein ◽  
Human Cytomegalovirus ◽  
Latent Infection ◽  
Lytic Replication ◽  
Wild Type ◽  
G Protein Coupled Receptor ◽  
In Trans ◽  
G Protein Coupled

AbstractHuman cytomegalovirus (HCMV) is a ubiquitous pathogen that undergoes latency in cells of the hematopoietic compartment, though the mechanisms underlying establishment and maintenance of latency remain elusive. We previously reported that the HCMV-encoded G-protein coupled receptor (GPCR) homolog,US28is required for successful latent infection. We now show that US28 protein (pUS28) providedin transcomplements the US28Δ lytic phenotype in myeloid cells, suggesting that sustained US28 expression is necessary for long-term latency. Furthermore, expression of pUS28 at the time of infection represses transcription from the major immediate early promoter (MIEP) within 24 hours. However, this repression is only maintained in the presence of continual pUS28 expression providedin trans. Our data also reveal that pUS28-mediated signaling attenuates both expression and phosphorylation of cellular fos (c-fos), an AP-1 transcription factor subunit, to repress MIEP-driven transcription. AP-1 binds to the MIEP and promotes lytic replication, and in line with this, we find that US28Δ infection results in an increase in AP-1 binding to the MIEP, compared to wild type latent infection. Pharmacological inhibition of c-fos represses the MIEP during US28Δ infection to similar levels we observe during wild type latent infection. Together, our data reveal that US28 is required for both establishment and long-term maintenance of HCMV latency, which is modulated, at least in part, by repressing functional AP-1 binding to the MIEP.Significance StatementHuman cytomegalovirus (HCMV) is a wise-spread pathogen that remains with an individual for life in a quiescent/latent state, posing little threat to an otherwise healthy person. However, when an individual’s immune system is severely compromised, HCMV can reactivate to its active/lytic state, resulting in viral spread and disease that is often fatal. The biological mechanisms underlying HCMV latency and reactivation remain poorly understood. Herein we show that the viral-encoded G-protein coupled receptor (GPCR)US28aids in the establishment and the maintenance of viral latency. Furthermore, we find that US28 modulates host cell proteins to suppress viral processes associated with active/lytic replication, thereby promoting latent infection. This work provides mechanism by which HCMV modulates the host cell environment to its advantage.

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