scholarly journals Estradiol Acts Directly and Indirectly on Multiple Signaling Pathways to Phosphorylate cAMP-Response Element Binding Protein in GnRH Neurons

Endocrinology ◽  
2012 ◽  
Vol 153 (8) ◽  
pp. 3792-3803 ◽  
Author(s):  
Rachel Y. Cheong ◽  
Andrea Kwakowsky ◽  
Zsuzsanna Barad ◽  
Robert Porteous ◽  
Allan E. Herbison ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Camp Response Element Binding ◽  
Type Ii ◽  
Camp Response Element ◽  
Dependent Protein Kinase ◽  
Calcium Calmodulin Dependent ◽  
Gnrh Neurons ◽  
Element Binding Protein ◽  
Dependent Protein

Rapid, nonclassical 17β-estradiol (E2) actions are thought to play an important role in the modulation of neuronal function. The present study addresses the intracellular signaling cascades involved in the rapid E2-induced phosphorylation of cAMP response element binding protein (CREB) in GnRH neurons. Administration of E2 to adult female mice resulted in the activation of ERK1/2 in GnRH neurons within 15 min. In vitro studies using pharmacological antagonists showed that ERK1/2 was essential for E2-induced CREB phosphorylation in GnRH neurons. Upstream to this, protein kinase A and calcium/calmodulin-dependent protein kinase type II, but not protein kinase C, were found to be necessary for E2-induced phosphorylation of ERK1/2. This rapid E2 signaling cascade in GnRH neurons was found to require both direct and indirect E2 actions. E2 failed to phosphorylate ERK1/2 and CREB in GnRH neuron-specific estrogen receptor β knockout mice in vivo. Equally, however, a cocktail of tetrodotoxin and γ-aminobutyric acidA/glutamate receptor antagonists also blocked E2-induced ERK1/2 phosphorylation in GnRH neurons in wild-type mice in vitro. Together, these observations indicate that E2 acts through calcium/calmodulin-dependent protein kinase type II and protein kinase A to rapidly phosphorylate ERK1/2, which then acts to phosphorylate CREB in adult female GnRH neurons. Intriguingly, these effects of E2 are dependent upon both direct ERβ mechanisms as well as indirect actions mediated by afferent inputs to GnRH neurons.

Scutellarin Mitigates Cancer-Induced Bone Pain by Suppressing CaMKII/CREB Pathway in Rat Models

2019 ◽  
Vol 17 (3) ◽  
pp. 249-253
Author(s):  
Liu Chenglong ◽  
Liu Haihua ◽  
Zhang Fei ◽  
Zheng Jie ◽  
Wei Fang
Keyword(s):  
Protein Kinase ◽  
Bone Pain ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Camp Response Element ◽  
Dependent Protein Kinase ◽  
Response Element ◽  
Protein Kinase Ii ◽  
Element Binding Protein ◽  
Dependent Protein

Cancer-induced bone pain is a severe and complex pain caused by metastases to bone in cancer patients. The aim of this study was to investigate the analgesic effect of scutellarin on cancer-induced bone pain in rat models by intrathecal injection of Walker 256 carcinoma cells. Mechanical allodynia was determined by paw withdrawal threshold in response to mechanical stimulus, and thermal hyperalgesia was indicated by paw withdrawal latency in response to noxious thermal stimulus. The paw withdrawal threshold and paw withdrawal latencies were significantly decreased after inoculation of tumor cells, whereas administration of scutellarin significantly attenuated tumor cell inoculation-induced mechanical and heat hyperalgesia. Tumor cell inoculation-induced tumor growth was also significantly abrogated by scutellarin. Ca2+/calmodulin-dependent protein kinase II is a multifunctional kinase with up-regulated activity in bone pain models. The activation of Ca2+/calmodulin-dependent protein kinase II triggers phosphorylation of cAMP-response element binding protein. Scutellarin significantly reduced the expression of phosphorylated-Ca2+/calmodulin-dependent protein kinase II and phosphorylated-cAMP-response element binding protein in cancer-induced bone pain rats. Collectively, our study demonstrated that scutellarin attenuated tumor cell inoculation-induced bone pain by down-regulating the expression of phosphorylated-Ca2+/calmodulin-dependent protein kinase II and phosphorylated-cAMP-response element binding protein. The suppressive effect of scutellarin on phosphorylated-Ca2+/calmodulin-dependent protein kinase II/phosphorylated-cAMP-response element binding protein activation may serve as a novel therapeutic strategy for CIBP management.

cAMP-dependent protein kinase, but not the cGMP-dependent enzyme, rapidly phosphorylates Δ-CREB, and a synthetic Δ-CREB peptide

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1277-1282 ◽  
Author(s):  
Janet L. Colbran ◽  
Peter J. Roach ◽  
Carol J. Fiol ◽  
Jack E. Dixon ◽  
Ourania M. Andrisani ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Synthetic Peptide ◽  
Camp Response Element Binding ◽  
Camp Response Element ◽  
Dependent Protein Kinase ◽  
Intact Cells ◽  
Cgmp Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Element Binding Protein ◽  
Dependent Protein

Phosphorylation of the cAMP response element binding protein (CREB) by the catalytic subunit of cAMP-dependent protein kinase (cAK) has been implicated in the cAMP-dependent stimulation of gene transcription. Δ-CREB, a spliced variant of CREB, and CREBtide (KRREILSRRPSYR), a synthetic peptide based on the phosphorylation sequence in Δ-CREB, were tested as substrates of cAK. Phosphorylation of Δ-CREB (0.17 μM) was stoichiometric within 30 s when using a concentration of cAK which approximated the intracellular level (0.2 μM). The rate of phosphorylation of Δ-CREB was comparable to the rates of the best physiological substrates of cAK tested. The rate of CREBtide phosphorylation was at least as great as that of Δ-CREB, indicating that the peptide retained the determinants of Δ-CREB which were responsible for substrate efficacy. The apparent Km of CREBtide phosphorylation by cAK was 3.9 μM, which is 10-fold lower than that of kemptide (Km = 39 μM), the synthetic peptide substrate most often employed for cAK measurement. The Vmax values were 12.4 μmol/(min∙mg) for CREBtide and 9.8 μmol/(min∙mg) for kemptide. The apparent Km of CREBtide phosphorylation by cGMP-dependent protein kinase (cGK) was 2.9 μM and the Vmax value was 3.2 μmol/(min∙mg). Both Δ-CREB and CREBtide were phosphorylated at a much slower rate by cGK as compared with cAK, implying that the high cAK/cGK specificity exhibited by Δ-CREB was retained by the peptide. Taken together, the results indicated that Δ-CREB and CREBtide are among the best substrates tested for cAK and suggested that phosphorylation of CREB by this enzyme could occur in intact cells. However, cGK does not appear to be an adequate catalyst for this reaction.Key words: cAMP-dependent protein kinase, cGMP-dependent protein kinase, CREB.

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