Regulation of phosphorylation of Gi2α protein controls the secretory response to isoproterenol in rat parotid tissues
| Autor: | Hajime Ishida, Takafumi Eguchi, Yasuko Ishikawa, Ichiro Amano |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Male
medicine.medical_specialty Down-Regulation (Rat) Pertussis toxin Dephosphorylation chemistry.chemical_compound Ethers Cyclic GTP-Binding Proteins Internal medicine Okadaic Acid Receptors Adrenergic beta Phosphoprotein Phosphatases medicine Animals Parotid Gland Amylase Enzyme Inhibitors Phosphorylation Rats Wistar Protein kinase A Molecular Biology Guanine-nucleotide-binding protein Adenosine Diphosphate Ribose biology Isoproterenol Cell Biology Okadaic acid Cyclic AMP-Dependent Protein Kinases Molecular biology Rats Up-Regulation Endocrinology chemistry Guanosine 5'-O-(3-Thiotriphosphate) ADP-ribosylation Amylases biology.protein Alkaline phosphatase Amylase secretion Secretory Rate Signal Transduction |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Molecular Cell Research. 1313:146-156 |
| ISSN: | 0167-4889 |
| DOI: | 10.1016/0167-4889(96)00060-2 |
| Popis: | Treatment of rat parotid tissues with 1 microM isoproterenol (IPR) for 10 min caused a 60% decrease in pertussis toxin (IAP)-catalyzed ADP-ribosylation of Gi alpha and resulted in supersensitivity of amylase secretion from the tissues. However, conversely, IPR treatment for 30 min caused a 40% increase in IAP-catalyzed ADP-ribosylation of Gi alpha, coupled with desensitization of amylase secretion. No changes in Gs function were observed in IPR-induced phenomena. Pretreatment with okadaic acid induced enhancement of the supersensitivity of amylase secretion and disappearance of the desensitization. These phenomena were accompanied with decreases in IAP-catalyzed ADP-ribosylation of Gi alpha. IPR treatment for 30 min caused a 50% decrease in phosphorylation of Gi2 alpha immunoprecipitated with anti-G protein antiserum (AS/7) from [32P]Pi-labeled cells, but such treatment for 10 min caused a 40% increase in phosphorylation in the cells pretreated with okadaic acid. Phosphorylation and dephosphorylation of immunoprecipitates with AS/7 by protein kinase A (PKA) and alkaline phosphatase caused decreases and increases in IAP-catalyzed ADP-ribosylation, respectively, indicating the presence of PKA-mediated phosphorylation sites on Gi2 alpha. Thus, the control of the phosphorylation of Gi2 alpha is of importance and relevance in the regulation of biological processes and cellular responses. |
| Databáze: | OpenAIRE |
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