scholarly journals Mechanistic Differences in the Activation of Estrogen Receptor-α (ERα)- and ERβ-dependent Gene Expression by cAMP Signaling Pathway(s)

2003 ◽  
Vol 278 (15) ◽  
pp. 12834-12845 ◽  
Author(s):  
Kevin M. Coleman ◽  
Martin Dutertre ◽  
Abeer El-Gharbawy ◽  
Brian G. Rowan ◽  
Nancy L. Weigel ◽  
...  
2007 ◽  
Vol 27 (6) ◽  
pp. 2027-2036 ◽  
Author(s):  
Hsin-Chieh Lan ◽  
Hua-Jung Li ◽  
Guang Lin ◽  
Pao-Yen Lai ◽  
Bon-chu Chung

ABSTRACT Steroids are synthesized in adrenal glands and gonads under the control of pituitary peptides. These peptides bind to cell surface receptors to activate the cyclic AMP (cAMP) signaling pathway leading to an increase of steroidogenic gene expression. Exactly how cAMP activates steroidogenic gene expression is not clear, except for the knowledge that transcription factor SF-1 plays a key role. Investigating the factors participating in SF-1 action, we found that c-Jun and homeodomain-interacting protein kinase 3 (HIPK3) were required for basal and cAMP-stimulated expression of one major steroidogenic gene, CYP11A1. HIPK3 enhanced SF-1 activity, and c-Jun was required for the functional interaction of HIPK3 with SF-1. Furthermore, after cAMP stimulation, both c-Jun and Jun N-terminal kinase (JNK) were phosphorylated through HIPK3. These phosphorylations were important for SF-1 activity and CYP11A1 expression. Thus, we have defined HIPK3-mediated JNK activity and c-Jun phosphorylation as important events that increase SF-1 activity for CYP11A1 transcription in response to cAMP. This finding has linked three common factors, HIPK3, JNK, and c-Jun, to the cAMP signaling pathway leading to increased steroidogenic gene expression.


2010 ◽  
Vol 47 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Fernanda Zanolli Freitas ◽  
Renato Magalhães de Paula ◽  
Luiz Carlos Bertucci Barbosa ◽  
Hector Francisco Terenzi ◽  
Maria Célia Bertolini

2007 ◽  
Vol 6 (10) ◽  
pp. 1824-1840 ◽  
Author(s):  
Michael J. Wolyniak ◽  
Paula Sundstrom

ABSTRACT Changes in gene expression during reversible bud-hypha transitions of the opportunistic fungal pathogen Candida albicans permit adaptation to environmental conditions that are critical for proliferation in host tissues. Our previous work has shown that the hypha-specific adhesin gene HWP1 is up-regulated by the cyclic AMP (cAMP) signaling pathway. However, little is known about the potential influences of determinants of cell morphology on HWP1 gene expression. We found that blocking hypha formation with cytochalasin A, which destabilizes actin filaments, and with latrunculin A, which sequesters actin monomers, led to a loss of HWP1 gene expression. In contrast, high levels of HWP1 gene expression were observed when the F-actin stabilizer jasplakinolide was used to block hypha formation, suggesting that HWP1 expression could be regulated by actin structures. Mutants defective in formin-mediated nucleation of F-actin were reduced in HWP1 gene expression, providing genetic support for the importance of actin structures. Kinetic experiments with wild-type and actin-deficient cells revealed two distinct phases of HWP1 gene expression, with a slow, actin-independent phase preceding a fast, actin-dependent phase. Low levels of HWP1 gene expression that appeared to be independent of stabilized actin and cAMP signaling were detected using indirect immunofluorescence. A connection between actin structures and the cAMP signaling pathway was shown using hyper- and hypomorphic cAMP mutants, providing a possible mechanism for up-regulation of HWP1 gene expression by stabilized actin. The results reveal a new role for F-actin as a regulatory agent of hypha-specific gene expression at the bud-hypha transition.


Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 896
Author(s):  
Jan Zmazek ◽  
Vladimir Grubelnik ◽  
Rene Markovič ◽  
Marko Marhl

Glucose metabolism plays a crucial role in modulating glucagon secretion in pancreatic alpha cells. However, the downstream effects of glucose metabolism and the activated signaling pathways influencing glucagon granule exocytosis are still obscure. We developed a computational alpha cell model, implementing metabolic pathways of glucose and free fatty acids (FFA) catabolism and an intrinsically activated cAMP signaling pathway. According to the model predictions, increased catabolic activity is able to suppress the cAMP signaling pathway, reducing exocytosis in a Ca2+-dependent and Ca2+ independent manner. The effect is synergistic to the pathway involving ATP-dependent closure of KATP channels and consequent reduction of Ca2+. We analyze the contribution of each pathway to glucagon secretion and show that both play decisive roles, providing a kind of “secure double switch”. The cAMP-driven signaling switch plays a dominant role, while the ATP-driven metabolic switch is less favored. The ratio is approximately 60:40, according to the most recent experimental evidence.


Bone ◽  
2010 ◽  
Vol 46 (3) ◽  
pp. 628-642 ◽  
Author(s):  
Gul Zaman ◽  
Leanne K. Saxon ◽  
Andrew Sunters ◽  
Helen Hilton ◽  
Peter Underhill ◽  
...  

2012 ◽  
Vol 302 (6) ◽  
pp. C839-C852 ◽  
Author(s):  
Wei P. Feinstein ◽  
Bing Zhu ◽  
Silas J. Leavesley ◽  
Sarah L. Sayner ◽  
Thomas C. Rich

Cyclic AMP signals encode information required to differentially regulate a wide variety of cellular responses; yet it is not well understood how information is encrypted within these signals. An emerging concept is that compartmentalization underlies specificity within the cAMP signaling pathway. This concept is based on a series of observations indicating that cAMP levels are distinct in different regions of the cell. One such observation is that cAMP production at the plasma membrane increases pulmonary microvascular endothelial barrier integrity, whereas cAMP production in the cytosol disrupts barrier integrity. To better understand how cAMP signals might be compartmentalized, we have developed mathematical models in which cellular geometry as well as total adenylyl cyclase and phosphodiesterase activities were constrained to approximate values measured in pulmonary microvascular endothelial cells. These simulations suggest that the subcellular localizations of adenylyl cyclase and phosphodiesterase activities are by themselves insufficient to generate physiologically relevant cAMP gradients. Thus, the assembly of adenylyl cyclase, phosphodiesterase, and protein kinase A onto protein scaffolds is by itself unlikely to ensure signal specificity. Rather, our simulations suggest that reductions in the effective cAMP diffusion coefficient may facilitate the formation of substantial cAMP gradients. We conclude that reductions in the effective rate of cAMP diffusion due to buffers, structural impediments, and local changes in viscosity greatly facilitate the ability of signaling complexes to impart specificity within the cAMP signaling pathway.


2015 ◽  
Vol 758 ◽  
pp. 24-30 ◽  
Author(s):  
Fabiano Beraldi Calmasini ◽  
Luiz Osório Silveira Leiria ◽  
Marcos José Alves ◽  
Fernando Ricardo Báu ◽  
Eduardo Costa Alexandre ◽  
...  

ChemInform ◽  
2010 ◽  
Vol 41 (48) ◽  
pp. no-no
Author(s):  
Julie Daoust ◽  
Angelo Fontana ◽  
Catherine E. Merchant ◽  
Nicole J. de Voogd ◽  
Brian O. Patrick ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document