The interleukin-6 (IL-6)/IL-6-receptor system induces human chorionic gonadotropin production by activating tyrosine kinase-dependent signal transduction pathway different from pathways triggered by protein kinase activators including gonadotropin releasing hormone

1993 ◽  
Vol 77 (3) ◽  
pp. 704-709 ◽  
Author(s):  
R. Neki
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Interleukin 6 ◽  
Signal Transduction Pathway ◽  
Gonadotropin Releasing Hormone ◽  
Transduction Pathway ◽  
Receptor System ◽  
Dependent Signal

scholarly journals Up-Regulation of Placental Leptin by Human Chorionic Gonadotropin

Endocrinology ◽  
2008 ◽  
Vol 150 (1) ◽  
pp. 304-313 ◽  
Author(s):  
Julieta L. Maymó ◽  
Antonio Pérez Pérez ◽  
Víctor Sánchez-Margalet ◽  
José L. Dueñas ◽  
Juan Carlos Calvo ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Western Blot ◽  
Reporter Gene ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Promoter Regions ◽  
Leptin Expression ◽  
Dose Dependent

Leptin, the 16,000 molecular weight protein product of the obese gene, was originally considered as an adipocyte-derived signaling molecule for the central control of metabolism. However, leptin has been suggested to be involved in other functions during pregnancy, particularly in placenta, in which it was found to be expressed. In the present work, we have found that recombinant human chorionic gonadotropin (hCG) added to BeWo choriocarcinoma cell line showed a stimulatory effect on endogenous leptin expression, when analyzed by Western blot. This effect was time and dose dependent. Maximal effect was achieved at hCG 100 IU/ml. Moreover, hCG treatment enhanced leptin promoter activity up to 12.9 times, evaluated by transient transfection with a plasmid construction containing different promoter regions and the reporter gene luciferase. This effect was dose dependent and evidenced with all the promoter regions analyzed, regardless of length. Similar results were obtained with placental explants, thus indicating physiological relevance. Because hCG signal transduction usually involves cAMP signaling, this pathway was analyzed. Contrarily, we found that dibutyryl cAMP counteracted hCG effect on leptin expression. Furthermore, cotransfection with the catalytic subunit of PKA and/or the transcription factor cAMP response element binding protein repressed leptin expression. Thereafter we determined that hCG effect could be partially blocked by pharmacologic inhibition of MAPK pathway with 50 μM PD98059 but not by the inhibition of the phosphatidylinositol 3-kinase pathway with 0.1 μm wortmannin. Moreover, hCG treatment promoted MAPK kinase and ERK1/ERK2 phosphorylation in placental cells. Finally, cotransfection with a dominant-negative mutant of MAPK blocked the hCG-mediated activation of leptin expression. In conclusion, we provide some evidence suggesting that hCG induces leptin expression in trophoblastic cells probably involving the MAPK signal transduction pathway. Human chorionic gonadotropin induces leptin expression in trophoblastic BeWo cells and placental explants analyzed by western-blot and reporter gene strategy. This effect involves the MAPK signal transduction pathway.

Far1 and Fus3 link the mating pheromone signal transduction pathway to three G1-phase Cdc28 kinase complexes

1993 ◽  
Vol 13 (9) ◽  
pp. 5659-5669 ◽  
Author(s):  
M Tyers ◽  
B Futcher
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
Signal Transduction Pathway ◽  
Mitogen Activated Protein Kinase ◽  
G1 Phase ◽  
Transduction Pathway ◽  
Yeast Saccharomyces Cerevisiae ◽  
Alpha Factor ◽  
Mitogen Activated Protein

In the yeast Saccharomyces cerevisiae, the Cdc28 protein kinase controls commitment to cell division at Start, but no biologically relevant G1-phase substrates have been identified. We have studied the kinase complexes formed between Cdc28 and each of the G1 cyclins Cln1, Cln2, and Cln3. Each complex has a specific array of coprecipitated in vitro substrates. We identify one of these as Far1, a protein required for pheromone-induced arrest at Start. Treatment with alpha-factor induces a preferential association and/or phosphorylation of Far1 by the Cln1, Cln2, and Cln3 kinase complexes. This induced interaction depends upon the Fus3 protein kinase, a mitogen-activated protein kinase homolog that functions near the bottom of the alpha-factor signal transduction pathway. Thus, we trace a path through which a mitogen-activated protein kinase regulates a Cdc2 kinase.

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