scholarly journals Angiotensin II-Mediated Protein Kinase D Activation Stimulates Aldosterone and Cortisol Secretion in H295R Human Adrenocortical Cells

Endocrinology ◽  
2006 ◽  
Vol 147 (12) ◽  
pp. 6046-6055 ◽  
Author(s):  
Damian G. Romero ◽  
Bronwyn L. Welsh ◽  
Elise P. Gomez-Sanchez ◽  
Licy L. Yanes ◽  
Silvia Rilli ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Protein Kinase D ◽  
Cell Physiology ◽  
Cortisol Secretion ◽  
Adrenal Cells ◽  
Constitutively Active

Protein kinases are important mediators in intracellular signaling. Angiotensin II is the most important modulator of adrenal zona glomerulosa cell physiology. Angiotensin II regulates steroidogenesis and proliferation among many other metabolic processes. H295R human adrenal cells are a widely used experimental model to study adrenal cell physiology and metabolism. We screened for protein kinase expression levels using the Kinetwork system in H295R cells after 3 h angiotensin II treatment. Protein kinase D (PKD) was the protein kinase that suffers the most dramatic changes. PKD is a member of a new class of serine/threonine protein kinases that is activated by phosphorylation. Our studies indicated that angiotensin II time- and dose-dependently increased PKD phosphorylation, which occurred within 2 min of angiotensin II treatment and at concentrations as low as 1 nm. PKD phosphorylation was also dose-dependently increased by the PKC activator phorbol 12-myristate 13-acetate. Angiotensin II-mediated PKD phosphorylation was blocked by several PKC inhibitors. Furthermore, PKCε translocation inhibitor peptide decreased angiotensin II-mediated PKD phosphorylation, and PKCε down-regulation by RNA interference also decreased PKD phosphorylation mediated by angiotensin II. Cotransfection of constitutively active PKD mutant constructs up-regulated aldosterone synthase and 11β-hydroxylase expression in reporter assays. Constitutively active PKD mutants increased aldosterone and cortisol secretion under angiotensin II stimulatory conditions. This study reveals that PKD is an intracellular signaling mediator of angiotensin II regulation of steroidogenesis in human adrenal cells. These data provide new insights into the molecular mechanisms involved in angiotensin II-induced physiological and pathophysiological events in adrenal cells.

scholarly journals Angiotensin II-Induced Protein Kinase D Activates the ATF/CREB Family of Transcription Factors and Promotes StAR mRNA Expression

Endocrinology ◽  
2014 ◽  
Vol 155 (7) ◽  
pp. 2524-2533 ◽  
Author(s):  
Lawrence O. Olala ◽  
Vivek Choudhary ◽  
Maribeth H. Johnson ◽  
Wendy B. Bollag
Keyword(s):  
Transcription Factors ◽  
Angiotensin Ii ◽  
Protein Kinase ◽  
Mrna Expression ◽  
Dominant Negative ◽  
Protein Kinase D ◽  
Dependent Manner ◽  
Aldosterone Production ◽  
Glomerulosa Cells ◽  
Constitutively Active

Aldosterone synthesis is initiated upon the transport of cholesterol from the outer to the inner mitochondrial membrane, where the cholesterol is hydrolyzed to pregnenolone. This process is the rate-limiting step in acute aldosterone production and is mediated by the steroidogenic acute regulatory (StAR) protein. We have previously shown that angiotensin II (AngII) activation of the serine/threonine protein kinase D (PKD) promotes acute aldosterone production in bovine adrenal glomerulosa cells, but the mechanism remains unclear. Thus, the purpose of this study was to determine the downstream signaling effectors of AngII-stimulated PKD activity. Our results demonstrate that overexpression of the constitutively active serine-to-glutamate PKD mutant enhances, whereas the dominant-negative serine-to-alanine PKD mutant inhibits, AngII-induced StAR mRNA expression relative to the vector control. PKD has been shown to phosphorylate members of the activating transcription factor (ATF)/cAMP response element binding protein (CREB) family of leucine zipper transcription factors, which have been shown previously to bind the StAR proximal promoter and induce StAR mRNA expression. In primary glomerulosa cells, AngII induces ATF-2 and CREB phosphorylation in a time-dependent manner. Furthermore, overexpression of the constitutively active PKD mutant enhances the AngII-elicited phosphorylation of ATF-2 and CREB, and the dominant-negative mutant inhibits this response. Furthermore, the constitutively active PKD mutant increases the binding of phosphorylated CREB to the StAR promoter. Thus, these data provide insight into the previously reported role of PKD in AngII-induced acute aldosterone production, providing a mechanism by which PKD may be mediating steroidogenesis in primary bovine adrenal glomerulosa cells.

scholarly journals Phosphorylation Sites in Protein Kinases and Phosphatases Regulated by Formyl Peptide Receptor 2 Signaling

2020 ◽  
Vol 21 (11) ◽  
pp. 3818
Author(s):  
Maria Carmela Annunziata ◽  
Melania Parisi ◽  
Gabriella Esposito ◽  
Gabriella Fabbrocini ◽  
Rosario Ammendola ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Protein Phosphatase ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Fine Tuning ◽  
Formyl Peptide Receptor ◽  
Signaling Cascades ◽  
Regulatory Subunit ◽  
Formyl Peptides

FPR1, FPR2, and FPR3 are members of Formyl Peptides Receptors (FPRs) family belonging to the GPCR superfamily. FPR2 is a low affinity receptor for formyl peptides and it is considered the most promiscuous member of this family. Intracellular signaling cascades triggered by FPRs include the activation of different protein kinases and phosphatase, as well as tyrosine kinase receptors transactivation. Protein kinases and phosphatases act coordinately and any impairment of their activation or regulation represents one of the most common causes of several human diseases. Several phospho-sites has been identified in protein kinases and phosphatases, whose role may be to expand the repertoire of molecular mechanisms of regulation or may be necessary for fine-tuning of switch properties. We previously performed a phospho-proteomic analysis in FPR2-stimulated cells that revealed, among other things, not yet identified phospho-sites on six protein kinases and one protein phosphatase. Herein, we discuss on the selective phosphorylation of Serine/Threonine-protein kinase N2, Serine/Threonine-protein kinase PRP4 homolog, Serine/Threonine-protein kinase MARK2, Serine/Threonine-protein kinase PAK4, Serine/Threonine-protein kinase 10, Dual specificity mitogen-activated protein kinase kinase 2, and Protein phosphatase 1 regulatory subunit 14A, triggered by FPR2 stimulation. We also describe the putative FPR2-dependent signaling cascades upstream to these specific phospho-sites.

scholarly journals Ca2+ Microdomains, Calcineurin and the Regulation of Gene Transcription

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 875
Author(s):  
Gerald Thiel ◽  
Tobias Schmidt ◽  
Oliver G. Rössler
Keyword(s):  
Transcription Factors ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Gene Transcription ◽  
Intracellular Signaling ◽  
Second Messengers ◽  
Major Function ◽  
Surface Receptors ◽  
Dependent Protein

Ca2+ ions function as second messengers regulating many intracellular events, including neurotransmitter release, exocytosis, muscle contraction, metabolism and gene transcription. Cells of a multicellular organism express a variety of cell-surface receptors and channels that trigger an increase of the intracellular Ca2+ concentration upon stimulation. The elevated Ca2+ concentration is not uniformly distributed within the cytoplasm but is organized in subcellular microdomains with high and low concentrations of Ca2+ at different locations in the cell. Ca2+ ions are stored and released by intracellular organelles that change the concentration and distribution of Ca2+ ions. A major function of the rise in intracellular Ca2+ is the change of the genetic expression pattern of the cell via the activation of Ca2+-responsive transcription factors. It has been proposed that Ca2+-responsive transcription factors are differently affected by a rise in cytoplasmic versus nuclear Ca2+. Moreover, it has been suggested that the mode of entry determines whether an influx of Ca2+ leads to the stimulation of gene transcription. A rise in cytoplasmic Ca2+ induces an intracellular signaling cascade, involving the activation of the Ca2+/calmodulin-dependent protein phosphatase calcineurin and various protein kinases (protein kinase C, extracellular signal-regulated protein kinase, Ca2+/calmodulin-dependent protein kinases). In this review article, we discuss the concept of gene regulation via elevated Ca2+ concentration in the cytoplasm and the nucleus, the role of Ca2+ entry and the role of enzymes as signal transducers. We give particular emphasis to the regulation of gene transcription by calcineurin, linking protein dephosphorylation with Ca2+ signaling and gene expression.

scholarly journals Angiotensin II-activated protein kinase D mediates acute aldosterone secretion

2010 ◽  
Vol 317 (1-2) ◽  
pp. 99-105 ◽  
Author(s):  
Brian A. Shapiro ◽  
Lawrence Olala ◽  
Senthil Nathan Arun ◽  
Peter M. Parker ◽  
Mariya V. George ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Protein Kinase ◽  
Protein Kinase D ◽  
Aldosterone Secretion

scholarly journals The AGC Kinase SsAgc1 Regulates Sporisorium scitamineum Mating/Filamentation and Pathogenicity

mSphere ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Yixu Wang ◽  
Yi Zhen Deng ◽  
Guobing Cui ◽  
Chengwei Huang ◽  
Bin Zhang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Signaling Pathway ◽  
Protein Kinases ◽  
Molecular Mechanisms ◽  
Economic Losses ◽  
Signal Molecules ◽  
Dependent Protein Kinase ◽  
Sporisorium Scitamineum ◽  
Fungal Mating ◽  
Dependent Protein

ABSTRACT Sporisorium scitamineum is the fungal pathogen causing severe sugarcane smut disease that leads to massive economic losses globally. S. scitamineum invades host cane by dikaryotic hyphae, formed after sexual mating of two haploid sporidia of opposite mating type. Therefore, mating/filamentation is critical for S. scitamineum pathogenicity, while its molecular mechanisms remain largely unknown. The AGC (cyclic AMP [cAMP]-dependent protein kinase 1 [protein kinase A {PKA}], cGMP-dependent protein kinase [PKG], and protein kinase C [PKC]) kinase family is a group of serine/threonine (Ser/Thr) protein kinases conserved among eukaryotic genomes, serving a variety of physiological functions, including cell growth, metabolism, differentiation, and cell death. In this study, we identified an AGC kinase, named SsAgc1 (for S. scitamineum Agc1), and characterized its function by reverse genetics. Our results showed that SsAgc1 is critical for S. scitamineum mating/filamentation and pathogenicity, and oxidative stress tolerance under some circumstances. Transcriptional profiling revealed that the SsAgc1 signaling pathway may control expression of the genes governing fungal mating/filamentation and tryptophan metabolism, especially for tryptophol production. We showed that tryptophan and tryptophol could at least partially restore ssagc1Δ mating/filamentation. Overall, our work revealed a signaling pathway mediated by AGC protein kinases to regulate fungal mating/filamentation, possibly through sensing and responding to tryptophol as signal molecules. IMPORTANCE The AGC signaling pathway represents a conserved distinct signaling pathway in regulation of fungal differentiation and virulence, while it has not been identified or characterized in the sugarcane smut fungus Sporisorium scitamineum. In this study, we identified a PAS domain-containing AGC kinase, SsAgc1, in S. scitamineum. Functional analysis revealed that SsAgc1 plays a regulatory role on the fungal dimorphic switch.

scholarly journals Role of Calcium and EPAC in Norepinephrine-Induced Ghrelin Secretion

Endocrinology ◽  
2014 ◽  
Vol 155 (1) ◽  
pp. 98-107 ◽  
Author(s):  
Bharath K. Mani ◽  
Jen-Chieh Chuang ◽  
Lilja Kjalarsdottir ◽  
Ichiro Sakata ◽  
Angela K. Walker ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Intracellular Signaling ◽  
Endocrine Cells ◽  
Molecular Mechanisms ◽  
Phosphodiesterase Inhibitor ◽  
Intracellular Signaling Pathways ◽  
Ghrelin Secretion ◽  
Kinase A

Ghrelin is an orexigenic hormone secreted principally from a distinct population of gastric endocrine cells. Molecular mechanisms regulating ghrelin secretion are mostly unknown. Recently, norepinephrine (NE) was shown to enhance ghrelin release by binding to β1-adrenergic receptors on ghrelin cells. Here, we use an immortalized stomach-derived ghrelin cell line to further characterize the intracellular signaling pathways involved in NE-induced ghrelin secretion, with a focus on the roles of Ca2+ and cAMP. Several voltage-gated Ca2+ channel (VGCC) family members were found by quantitative PCR to be expressed by ghrelin cells. Nifedipine, a selective L-type VGCC blocker, suppressed both basal and NE-stimulated ghrelin secretion. NE induced elevation of cytosolic Ca2+ levels both in the presence and absence of extracellular Ca2+. Ca2+-sensing synaptotagmins Syt7 and Syt9 were also highly expressed in ghrelin cell lines, suggesting that they too help mediate ghrelin secretion. Raising cAMP with the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine also stimulated ghrelin secretion, although such a cAMP-mediated effect likely does not involve protein kinase A, given the absence of a modulatory response to a highly selective protein kinase A inhibitor. However, pharmacological inhibition of another target of cAMP, exchange protein-activated by cAMP (EPAC), did attenuate both basal and NE-induced ghrelin secretion, whereas an EPAC agonist enhanced basal ghrelin secretion. We conclude that constitutive ghrelin secretion is primarily regulated by Ca2+ influx through L-type VGCCs and that NE stimulates ghrelin secretion predominantly through release of intracellular Ca2+. Furthermore, cAMP and its downstream activation of EPAC are required for the normal ghrelin secretory response to NE.

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