scholarly journals Cyclic AMP (cAMP)-Mediated Stimulation of Adipocyte Differentiation Requires the Synergistic Action of Epac- and cAMP-Dependent Protein Kinase-Dependent Processes

2008 ◽  
Vol 28 (11) ◽  
pp. 3804-3816 ◽  
Author(s):  
Rasmus Koefoed Petersen ◽  
Lise Madsen ◽  
Lone Møller Pedersen ◽  
Philip Hallenborg ◽  
Hanne Hagland ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Cellular Response ◽  
Adipocyte Differentiation ◽  
Rho Kinase ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Dependent Processes ◽  
Stimulation Of

ABSTRACT Cyclic AMP (cAMP)-dependent processes are pivotal during the early stages of adipocyte differentiation. We show that exchange protein directly activated by cAMP (Epac), which functions as a guanine nucleotide exchange factor for the Ras-like GTPases Rap1 and Rap2, was required for cAMP-dependent stimulation of adipocyte differentiation. Epac, working via Rap, acted synergistically with cAMP-dependent protein kinase (protein kinase A [PKA]) to promote adipogenesis. The major role of PKA was to down-regulate Rho and Rho-kinase activity, rather than to enhance CREB phosphorylation. Suppression of Rho-kinase impaired proadipogenic insulin/insulin-like growth factor 1 signaling, which was restored by activation of Epac. This interplay between PKA and Epac-mediated processes not only provides novel insight into the initiation and tuning of adipocyte differentiation, but also demonstrates a new mechanism of cAMP signaling whereby cAMP uses both PKA and Epac to achieve an appropriate cellular response.

Chaperones, somatotroph tumors and the cyclic AMP (cAMP)-dependent protein kinase (PKA) pathway

2020 ◽  
Vol 499 ◽  
pp. 110607 ◽  
Author(s):  
Marie Helene Schernthaner-Reiter ◽  
Giampaolo Trivellin ◽  
Constantine A. Stratakis
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Pka Pathway

scholarly journals cAMP signaling in neurons: patterns of neuronal expression and intracellular localization for a novel protein, AKAP 150, that anchors the regulatory subunit of cAMP-dependent protein kinase II beta.

1992 ◽  
Vol 3 (11) ◽  
pp. 1215-1228 ◽  
Author(s):  
S B Glantz ◽  
J A Amat ◽  
C S Rubin
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Regulatory Subunit ◽  
Mammalian Brain ◽  
Dependent Protein Kinase ◽  
Intracellular Location ◽  
Anchor Protein ◽  
Camp Dependent Protein Kinase ◽  
Protein Kinase Ii ◽  
Dependent Protein

In mammalian brain, physiological signals carried by cyclic AMP (cAMP) seem to be targeted to effector sites via the tethering of cAMP-dependent protein kinase II beta (PKAII beta) to intracellular structures. Recently characterized A kinase anchor proteins (AKAPs) are probable mediators of the sequestration of PKAII beta because they contain a high-affinity binding site for the regulatory subunit (RII beta) of the kinase and a distinct intracellular targeting domain. To establish a cellular basis for this targeting mechanism, we have employed immunocytochemistry to 1) identify the types of neurons that are enriched in AKAPs, 2) determine the primary intracellular location of the anchor protein, and 3) demonstrate that an AKAP and RII beta are coenriched and colocalized in neurons that utilize the adenylate cyclase-cyclic AMP-dependent protein kinase (PKA) signaling pathway. Antibodies directed against rat brain AKAP 150 were used to elucidate the regional, cellular and intracellular distribution of a prototypic anchor protein in the CNS. AKAP 150 is abundant in Purkinje cells and in neurons of the olfactory bulb, basal ganglia, cerebral cortex, and other forebrain regions. In contrast, little AKAP 150 is detected in neurons of the thalamus, hypothalamus, midbrain, and hindbrain. A high proportion of total AKAP 150 is concentrated in primary branches of dendrites, where it is associated with microtubules. We also discovered that the patterns of accumulation and localization of RII beta (and PKAII beta) in brain are similar to those of AKAP 150. The results suggest that bifunctional AKAP 150 tethers PKAII beta to the dendritic cytoskeleton, thereby creating a discrete target site for the reception and propagation of signals carried by cAMP.

Stimulation of chick adrenal steroidogenesis by avian parathyroid hormone

1988 ◽  
Vol 116 (1) ◽  
pp. 91-95 ◽  
Author(s):  
J. Rosenberg ◽  
M. Pines ◽  
S. Hurwitz
Keyword(s):  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Steroid Hormone ◽  
Hormone Secretion ◽  
Peptide Hormone ◽  
Adrenocortical Cells ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Stimulation Of

ABSTRACT Dispersed chick adrenocortical cells were incubated with avian parathyroid hormone (aPTH) or ACTH. Accumulation of cyclic AMP (cAMP), activity of cAMP-dependent protein kinase and the secretion of corticosterone and aldosterone, in response to these hormones, were measured. Accumulation of cAMP and activity of cAMP-dependent protein kinase were stimulated by both aPTH and ACTH as well as by cholera toxin. Cyclic AMP production followed a similar time-course when stimulated by either peptide hormone. Stimulation of steroid hormone secretion was detectable after 20 min of incubation with ACTH, but only after 40 min with aPTH. The maximal steroid hormone secretion by adrenocortical cells was similar when induced by either peptide hormone. The aPTH concentrations needed for half-maximal response of corticosterone and aldosterone secretion were higher than those for ACTH (2·5- and 2-fold respectively), but still within the physiological range. The 11β-hydroxylase inhibitor metyrapone inhibited the secretion of both corticosterone and aldosterone when induced by either aPTH or ACTH. The results suggest that aPTH is almost as potent as ACTH in stimulating the secretion of corticosterone and aldosterone from chick adrenocortical cells and utilizes a cAMP-dependent pathway similar to that of ACTH. J. Endocr. (1988) 116, 91–95

Effects of isoproterenol on cylic-AMP metabolism in rat ventral prostate

1976 ◽  
Vol 54 (3) ◽  
pp. 327-335 ◽  
Author(s):  
B. K. Tsang ◽  
R. L. Singhal
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Kinase Activity ◽  
Activity Ratio ◽  
Ventral Prostate ◽  
Adrenergic Stimulation ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Stimulation Of

β-Adrenergic stimulation of the ventral prostate cyclic-AMP system was investigated by examining the influence of isoproterenol on endogenous cyclic-AMP levels as well as on the activities of adenylate cyclase (EC 4.6.1.1) and cyclic-AMP-dependent and independent protein kinases (EC 2.7.1.37). Administration of isoproterenol (1 mg/kg, ip) resulted in rapid elevation of adenylate cyclase activity (119%) and cyclic-AMP levels (593%). The observed isoproterenol-stimulated changes in cyclic-AMP metabolism of the ventral prostate were time-dependent and maximal stimulation was seen 5 min after treatment with this β-adrenergic agonist. The increases in prostatic adenylate cyclase and cyclic-AMP also were related to the dose of isoproterenol administered and maximal enhancement of these parameters was seen with 1 mg/kg dose of the agonist. Whereas pretreatment of rats with propranolol (3 mg/kg, ip) partially reversed these alterations, administration of an α-adrenergic antagonist, phentolamine, even at a dose of 5 mg/kg, failed to elicit any appreciable effect. Stimulation of prostatic soluble protein kinase by isoproterenol was associated with a decrease (33%) in the activity of the cyclic-AMP-dependent protein kinase with a concomitant increase (25%) in that of the independent enzyme. Whereas the ability of the enzyme to bind cyclic-[3H] AMP in vitro was decreased (54%) following isoproterenol treatment, the protein kinase activity ratio (−cyclic-AMP/+cyclic-AMP) was significantly elevated from 0.51 ± 0.05 to 0.95 ± 0.08. Although propranolol alone had little or no effect on these parameters, it inhibited partially the isoproterenol-induced alterations in cyclic-AMP-dependent protein kinase and the cyclic-AMP binding capacity. Treatment with propranolol also blocked the increases in the kinase activity ratio and in the activity of cyclic-AMP-independent enzyme seen with isoproterenol. Data suggest that the concentration of ventral prostate cyclic-AMP as well as the activities of adenylate cyclase and cyclic-AMP-dependent and independent form of protein kinases are subject to modulation by β-adrenergic stimulation.

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