Epidermal growth factor upregulates β-adrenergic receptor signaling in a human salivary cell line

2003 ◽  
Vol 284 (5) ◽  
pp. C1164-C1175 ◽  
Author(s):  
Chih-Ko Yeh ◽  
Tazuko K. Hymer ◽  
April L. Sousa ◽  
Bin-Xian Zhang ◽  
Meyer D. Lifschitz ◽  
...  
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Adenylyl Cyclase ◽  
Adrenergic Receptor ◽  
Mapk Pathway ◽  
Receptor Density ◽  
Adenylyl Cyclase Activity ◽  
Adenylyl Cyclase System ◽  
Epidermal Growth ◽  
Salivary Cell

The effects of epidermal growth factor (EGF) on the β-adrenergic receptor-coupled adenylyl cyclase system were studied in a human salivary cell line (HSY). The β-adrenergic agonist isoproterenol (10−5 M) stimulated adenylyl cyclase activity by ∼2-fold, and the isoproterenol response was increased 1.8-fold after prolonged (48 h) exposure to EGF (5 × 10−10 M). In contrast, enzyme activation via stimulatory prostaglandin receptors and by agents acting on nonreceptor components of the adenylyl cyclase system was not enhanced by EGF. β-Adrenergic receptor density, assessed by binding of the β-adrenergic receptor antagonist (−)-[125I]iodopindolol, was increased threefold after EGF treatment. Competition binding studies with unlabeled antagonists selective for β1- and β2-adrenergic receptor subtypes indicated that the increase in (−)-[125I]iodopindolol binding sites induced by EGF reflected an increased number of β2-adrenergic receptors. Likewise, Northern blot analysis of RNA from EGF-treated cells revealed selective induction of β2-adrenergic receptor mRNA, which was blocked by the RNA synthesis inhibitor actinomycin D. The increase in β-adrenergic receptor density produced by EGF was unaltered after phorbol ester-induced downregulation of protein kinase C (PKC). Enhancement of isoproterenol-responsive adenylyl cyclase activity and phosphorylation of mitogen-activated protein kinase (MAPK) by EGF were both blocked by the MAPK pathway inhibitor PD-98059. The results suggest that in HSY cells EGF enhances β-adrenergic responsiveness by upregulating β2-adrenergic receptor expression at the transcriptional level. Moreover, the stimulatory effect of EGF on β2-adrenergic receptor signaling appears to be mediated by the MAPK pathway and independent of PKC activation.

scholarly journals Epidermal Growth Factor-Induced Heterologous Desensitization of the Luteinizing Hormone/Choriogonadotopin Receptor in a Cell-Free Membrane Preparation Is Associated with the Tyrosine Phosphorylation of the Epidermal Growth Factor Receptor**This work was supported by USDA Grant NRICGP-9401432 (to M.H.D.).

Endocrinology ◽  
1999 ◽  
Vol 140 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Marilyn L. G. Lamm ◽  
Rajsree M. Rajagopalan-Gupta ◽  
Mary Hunzicker-Dunn
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Adenylyl Cyclase ◽  
Tyrosine Phosphorylation ◽  
Egf Receptor ◽  
Cyclase Activity ◽  
Adenylyl Cyclase Activity ◽  
Heterologous Desensitization ◽  
Dependent Protein ◽  
Epidermal Growth

Abstract Epidermal growth factor (EGF) attenuated hCG-stimulated adenylyl cyclase activity in rat luteal and follicular membranes. H7, an equipotent serine/threonine protein kinase inhibitor of cAMP-dependent protein kinases, cGMP-dependent protein kinases, and lipid-dependent protein kinase C, did not effect the ability of EGF to decrease hCG-responsive adenylyl cyclase activity, suggesting that a serine/threonine phosphorylation event catalyzed by these kinases was not critically involved in EGF-induced desensitization. Likewise, pertussis toxin-catalyzed ADP-ribosylation of a 40-kDa luteal membrane protein, which exhibited immunoreactivity with an antibody against Giα, did not hinder the ability of EGF to attenuate hCG-stimulated adenylyl cyclase activity, indicating that Gi did not mediate EGF-induced desensitization. Rather, EGF-induced heterologous desensitization of LH/CG receptor in ovarian membranes was closely associated with the specific and prominent tyrosine phosphorylation of the 170-kDa EGF receptor. Both EGF-stimulated autophosphorylation of EGF receptor and EGF-induced LH/CG receptor desensitization were attenuated by genistein, a tyrosine kinase inhibitor. These results suggest that tyrosine phosphorylation of the 170-kDa EGF receptor is a necessary component of the signaling pathway in EGF-induced heterologous desensitization of the LH/CG receptor.

scholarly journals Thyroid hormone promotes the phosphorylation of STAT3 and potentiates the action of epidermal growth factor in cultured cells

1999 ◽  
Vol 338 (2) ◽  
pp. 427-432 ◽  
Author(s):  
Hung-Yun LIN ◽  
Ai SHIH ◽  
Faith B. DAVIS ◽  
Paul J. DAVIS
Keyword(s):  
Growth Factor ◽  
Thyroid Hormone ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Nuclear Translocation ◽  
Thyroid Hormone Receptor ◽  
Mapk Pathway ◽  
Nuclear Fraction ◽  
Epidermal Growth ◽  
Fos Expression

We have examined the effects of l-thyroxine (T4) on the activation of signal transducer and activator of transcription 3 (STAT3) and on the STAT3-dependent induction of c-Fos expression by epidermal growth factor (EGF). T4, at a physiological concentration of 100 nM, caused tyrosine phosphorylation and nuclear translocation (i.e. activation) of STAT3 in HeLa cells in as little as 10–20 min. Activation by T4 of STAT3 was maximal at 30 min (15±4-fold enhancement; mean±S.E.M.) in 18 experiments. This effect was reproduced by T4–agarose (100 nM) and blocked by CGP 41251, genistein, PD 98059 and geldanamycin, inhibitors of protein kinase C (PKC), protein tyrosine kinase (PTK), mitogen-activated protein kinase (MAPK) kinase and Raf-1 respectively. Tyrosine-phosphorylated MAPK also appeared in nuclear fractions within 10 min of treatment with T4. In the nuclear fraction of T4-treated cells, MAPK immunoprecipitate also contained STAT3. The actions of T4 were similar in HeLa and CV-1 cells, which lack thyroid hormone receptor (TR), and in TR-replete skin fibroblasts (BG-9). T4 also potentiated the EGF-induced nuclear translocation of activated STAT1α and STAT3 and enhanced the EGF-stimulated expression of c-Fos. Hormone potentiation of EGF-induced signal transduction and c-Fos expression was inhibited by CGP 41251, geldanamycin and PD 98059. Therefore the non-genomically induced activation by T4 of STAT3, and the potentiation of EGF by T4, require activities of PKC, PTK and an intact MAPK pathway.

β-Adrenergic and antiadrenergic modulation of cardiac adenylyl cyclase is influenced by phosphorylation

2003 ◽  
Vol 285 (4) ◽  
pp. H1471-H1478 ◽  
Author(s):  
James G. Dobson ◽  
Lynne G. Shea ◽  
Richard A. Fenton
Keyword(s):  
Protein Kinase ◽  
Adenylyl Cyclase ◽  
Adrenergic Receptor ◽  
Kinase Inhibitor ◽  
Cyclase Activity ◽  
Adenylyl Cyclase Activity ◽  
Protein Substrates ◽  
Membrane Phosphorylation ◽  
Mediated Reduction ◽  
Kinase A

Adenosine protects the myocardium of the heart by exerting an antiadrenergic action via the adenosine A1 receptor (A1R). Because β1-adrenergic receptor (β1R) stimulation elicits myocardial protein phosphorylation, the present study investigated whether protein kinase A (PKA) catalyzed rat heart ventricular membrane phosphorylation affects the β1R adrenergic and A1R adenosinergic actions on adenylyl cyclase activity. Membranes were either phosphorylated with PKA in the absence/presence of a protein kinase inhibitor (PKI) or dephosphorylated with alkaline phosphatase (AP) and assayed for adenylyl cyclase activity (AC) in the presence of the β1R agonist isoproterenol (ISO) and/or the A1R agonist 2-chloro- N6-cyclopentyladenosine (CCPA). 32P incorporation into the protein substrates of 140–120, 43, and 29 kDa with PKA increased both the ISO-elicited activation of AC by 51–54% and the A1R-mediated reduction of the ISO-induced increase in AC by 29–50%, thereby yielding a total antiadrenergic effect of ∼78%. These effects of PKA were prevented by PKI. AP reduced the ISO-induced increase in AC and eliminated the antiadrenergic effect of CCPA. Immunoprecipitation of the solubilized membrane adenylyl cyclase with the use of a polyclonal adenylyl cyclase VI antibody indicated that the enzyme is phosphorylated by PKA. These results indicate that the cardioprotective effect of adenosine afforded by its antiadrenergic action is facilitated by cardiac membrane phosphorylation.

scholarly journals Activation of the Ras/Mitogen-Activated Protein Kinase Pathway by Kinase-Defective Epidermal Growth Factor Receptors Results in Cell Survival but Not Proliferation

1998 ◽  
Vol 18 (12) ◽  
pp. 7192-7204 ◽  
Author(s):  
Francesca Walker ◽  
Akiko Kato ◽  
L. Jorge Gonez ◽  
Margaret L. Hibbs ◽  
Normand Pouliot ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Growth Factor ◽  
Protein Kinase ◽  
Epidermal Growth Factor ◽  
Mapk Pathway ◽  
Family Members ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Epidermal Growth ◽  
Egfr Family

ABSTRACT Signalling by the epidermal growth factor (EGF) receptor (EGFR) has been studied intensively, but for most cell types the analysis is complicated by the fact that EGFR not only homodimerizes but can also form heterodimers with other EGFR family members. Heterodimerization is a particular problem in the study of EGFR mutants, where the true phenotype of the mutants is confounded by the contribution of the heterodimer partner to signal transduction. We have made use of the murine hemopoietic cell line BaF/3, which does not express EGFR family members, to express wild-type (WT) EGFR, three kinase-defective EGFR mutants (V741G, Y740F, and K721R), or a C-terminally truncated EGFR (CT957) and have measured their responses to EGF. We found that under the appropriate conditions EGF can stimulate cell proliferation of BaF/3 cells expressing WT or CT957 EGFRs but not that of cells expressing the kinase-defective mutants. However, EGF promotes the survival of BaF/3 cells expressing either of the kinase-defective receptors (V741G and Y740F), indicating that these receptors can still transmit a survival signal. Analysis of the early signalling events by the WT, V741G, and Y740F mutant EGF receptors indicated that EGF stimulates comparable levels of Shc phosphorylation, Shc–GRB-2 association, and activation of Ras, B-Raf, and Erk-1. Blocking the mitogen-activated protein kinase (MAPK) signalling pathway with the specific inhibitor PD98059 abrogates completely the EGF-dependent survival of cells expressing the kinase-defective EGFR mutants but has no effect on the EGF-dependent proliferation mediated by WT and CT957 EGFRs. Similarly, the Src family kinase inhibitor PP1 abrogates EGF-dependent survival without affecting proliferation. However blocking phosphatidylinositol-3-kinase or JAK-2 kinase with specific inhibitors does arrest growth factor-dependent cell proliferation. Thus, EGFR-mediated mitogenic signalling in BaF/3 cells requires an intact EGFR tyrosine kinase activity and appears to depend on the activation of both the JAK-2 and PI-3 kinase pathways. Activation of the Src family of kinases or of the Ras/MAPK pathway can, however, be initiated by a kinase-impaired EGFR and is linked to survival.

Effects of coronary arterial reperfusion on beta-adrenergic receptor-adenylyl cyclase coupling

1993 ◽  
Vol 264 (1) ◽  
pp. H196-H204 ◽  
Author(s):  
D. E. Vatner ◽  
K. Kiuchi ◽  
W. T. Manders ◽  
S. F. Vatner
Keyword(s):  
Adenylyl Cyclase ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Cyclase Activity ◽  
Receptor Density ◽  
Beta Adrenergic Receptors ◽  
Adenylyl Cyclase Activity ◽  
Beta Adrenergic Receptor ◽  
Beta Adrenergic ◽  
High Affinity

The effects of 1 h of coronary arterial occlusion (CAO) followed by 15 min reperfusion (CAR) were examined in nine conscious dogs. Ischemia was verified by decreased regional blood flow (radioactive microspheres) and loss of systolic regional wall motion in the ischemic zone. beta-Adrenergic receptor density assessed by 125I-labeled cyanopindolol binding in a crude membrane fraction tended to decrease but was not significantly different. However, adenylyl cyclase activity and the guanine nucleotide stimulatory protein (Gs) were reduced in ischemic subendocardium compared with nonischemic subendocardium. The fraction of beta-adrenergic receptors binding agonist with high affinity increased in ischemic subendocardial and subepicardial layers. Compared with prior data in experiments with 1 h CAO without CAR, the increase in beta-adrenergic receptor density that occurs with myocardial ischemia is rapidly reversed with CAR of 15 min duration, while the decreased fraction of receptors binding agonist with high affinity was reversed to an increase in high-affinity receptors. The global decreases in adenylyl cyclase and Gs, which have been observed with simple CAO, persist but are observed selectively in the previously ischemic subendocardium after CAR. Thus both CAO and CAR affect beta-adrenergic receptors and adenylyl cyclase differently. During CAR, increased numbers of beta-adrenergic receptors binding agonist with high affinity occur potentially as a compensatory mechanism in the face of persistent reductions in adenylyl cyclase activity and Gs.

Sign in / Sign up

Export Citation Format

Share Document