Adenylate cyclase regulation via proteasome-mediated modulation of Gαs levels

Naviglio, Silvio; Pagano, Mario; Romano, Maria; Sorrentino, Angela; Fusco, Anna; Illiano, Fausto; Chiosi, Emilio; Spina, Annamaria; Illiano, G.

doi:10.1016/j.cellsig.2004.03.012

Cited by 26 publications

(18 citation statements)

References 47 publications

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“…After various incubation times, cell extracts were prepared from monolayer cultured cells by collecting and centrifuging cells at 1200 rpm for 10 min, discarding the supernatant, resuspending the cell pellets in 0.4-1 mL lysis buffer (50 mM Tris-HCl, pH 7.5, 0.33 M sucrose, 5 g/mL leupeptin, 5 g/mL aprotinin, 10 g/mL pepstatin A, and 1 mM phenylmethylsulfonylfluoride [PMSF]), and disrupting the cells in a tightly fitting glass Dounce with 30 strokes. 24 The obtained total homogenate was recovered; some aliquots were taken for protein quantification, and some others were diluted in 4ϫ Laemmli buffer, boiled, and stored as samples for Western blotting analysis. The largest amount was used for membrane preparation.…”

Section: Preparation Of Cell Extractsmentioning

confidence: 99%

Adenylate Cyclase/cAMP Pathway Downmodulation Counteracts Apoptosis Induced by IFN-αin Human Epidermoid Cancer Cells

Naviglio

Spina

Marra

et al. 2007

Journal of Interferon & Cytokine Research

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We have reported previously that interferon-alpha (IFN-alpha) induces apoptosis that is counteracted by an epidermal growth factor (EGF) --> Ras --> extracellular signal-regulated kinase (ERK)-dependent survival response in human epidermoid cancer KB cells. We have studied the effects of the cytokine on the cAMP-dependent pathway in these cells. A decrease in the intracellular cAMP levels was recorded in KB cells treated with IFN-alpha, whereas forskolin induced an increase in the production of cAMP that was reduced in the presence of IFN-alpha, suggesting a reduction in the activity of adenylate cyclase (AC) induced by IFN-alpha. These effects were paralleled by significant change in the expression of some AC catalytic subunit(s) and by reduction in the activity of protein kinase A (PKA). 8-Br-cAMP completely antagonized the reduction of PKA activity induced by IFN-alpha, whereas PKA inhibitor KT5720 enhanced the reduction of the enzyme activity induced by IFN-alpha. We have found that IFN-alpha induced a decrease in cAMP response element binding protein (CREB) phosphorylation without changes in its total expression. The concomitant treatment with IFN-alpha and 8-Br-cAMP potentiated and KT5720 counteracted apoptosis induced by IFN-alpha alone. In conclusion, these data suggest that the decrease in AC/cAMP pathway activity is a survival response to the apoptosis induced by IFN-alpha. Therefore, this pathway could represent a target to enhance the antitumor activity of IFN-alpha.

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Section: Preparation Of Cell Extractsmentioning

confidence: 99%

Adenylate Cyclase/cAMP Pathway Downmodulation Counteracts Apoptosis Induced by IFN-αin Human Epidermoid Cancer Cells

Naviglio

Spina

Marra

et al. 2007

Journal of Interferon & Cytokine Research

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“…Both yeast and mammalian stimulatory G protein ␣ subunit (G ␣s ) proteins are ubiquitinated and degraded by the 26S proteasomes ( Figure 2). 90 -95 Interestingly, ␤ 2 AR stimulation leads to downregulation of mammalian G ␣s protein via the proteasomal pathway, 95 suggesting that the regulated degradation of G protein is yet another mechanism for fine tuning receptor signal transduction (Figure 2). In addition, proteasomal degradation has been reported for the olfactory (G ␣o ) 96 and inhibitory (G ␣i ) G protein subunits 97 as well as for both the G t 98 and ␤␥ subunits of retinal G protein transducin, 92 although whether these processes are choreographed by 7TMR activation is not known.…”

Section: Ubiquitination Of 7tmr Regulatory Proteins and Downstream Efmentioning

confidence: 99%

Seven-Transmembrane Receptors and Ubiquitination

Shenoy

2007

Circulation Research

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Abstract-Regulation of protein function by posttranslational modification plays an important role in many biological pathways. The most well known among such modifications is protein phosphorylation performed by highly specific protein kinases. In the past decade, however, covalent linkage of the low-molecular-weight protein ubiquitin to substrate proteins (protein ubiquitination) has proven to be yet another widely used mechanism of protein regulation playing a crucial role in virtually all aspects of cellular functions. This review highlights some of the recently discovered and provocative roles for ubiquitination in the regulation of the life cycle and signal transduction properties of 7-transmembrane receptors that serve to integrate many biological functions and play fundamental roles in cardiovascular homeostasis.

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“…39 In mammalian cells, ubiquitination of Gα s makes it a substrate for proteasomal degradation. 42 Modulation of other subtypes has also been shown to depend on the ubiquitination/proteasome system such as Gα i2 , 43 Gα o , 44 or even Gα i3 . 45 In the present study, the mechanism responsible for the modulation of the amounts of G protein subtypes in persistent inflammatory conditions could very well be ubiquitin/proteasome dependent, since mRNA levels are unchanged and trafficking does not seem to be involved.…”

Section: Discussionmentioning

confidence: 99%

Peripheral inflammatory injury alters the relative abundance of Gα subunits in the dorsal horn of the spinal cord and in the rostral ventromedial medulla of male rats

et al. 2017

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A diverse array of G protein-coupled receptors (GPCRs) is implicated in the modulation of nociception. The efficacy and potency of several GPCR agonists change as a consequence of peripheral inflammatory injury. Whether these changes reflect alterations in expression of the G proteins themselves is not known. This study examined the expression of transcripts and proteins for the α subunits of three classes of heteromeric G proteins in the dorsal horn of the spinal cord and the rostral ventromedial medulla (RVM) of male rats four days and two weeks after intraplantar injection of complete Freund’s adjuvant (CFA) or saline. Levels of Gα transcript in the dorsal horn or RVM were unchanged by CFA treatment. However, in the dorsal horn, Gαi protein decreased in cytosolic and membrane fractions four days after CFA treatment. Levels of Gαz protein decreased in the membrane fraction. Levels of the other Gα subunits did not differ. Levels of the Gα subunits were unchanged two weeks after CFA treatment. In the RVM, Gαz protein levels decreased in the cytosolic fraction four days after CFA treatment. No other differences were observed. Two weeks after CFA, the levels for all Gα subunits trended higher in the RVM. These data indicate that peripheral inflammatory injury induces subtle changes in the abundance of Gα subunits that is specific with respect to class, subcellular compartment, tissue, and time after injury. These changes have the potential to alter the balance of the different subcellular signaling pathways through which GPCR agonists act to modulate nociception.

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Adenylate cyclase regulation via proteasome-mediated modulation of Gαs levels

Cited by 26 publications

References 47 publications

Adenylate Cyclase/cAMP Pathway Downmodulation Counteracts Apoptosis Induced by IFN-αin Human Epidermoid Cancer Cells

Adenylate Cyclase/cAMP Pathway Downmodulation Counteracts Apoptosis Induced by IFN-αin Human Epidermoid Cancer Cells

Seven-Transmembrane Receptors and Ubiquitination

Peripheral inflammatory injury alters the relative abundance of Gα subunits in the dorsal horn of the spinal cord and in the rostral ventromedial medulla of male rats

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