Mechanism of cAMP-induced Ca2+ influx in Dictyostelium: role of phospholipase A2
| Autor: | Ralph Schaloske, Dieter Malchow |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Palmitic Acid
Peptide Biochemistry Phospholipases A chemistry.chemical_compound Phospholipase A2 GTP-Binding Proteins Heterotrimeric G protein Cyclic AMP Animals Dictyostelium Enzyme Inhibitors Molecular Biology Protein kinase C Protein Kinase C chemistry.chemical_classification Arachidonic Acid Ion Transport biology Kinase Proteins Cell Biology biology.organism_classification Genistein Cell biology Enzyme Activation Lipoprotein Lipase Phospholipases A2 chemistry biology.protein Arachidonic acid Calcium Tyrosine kinase Signal Transduction Research Article |
| Zdroj: | The Biochemical journal. 327 |
| ISSN: | 0264-6021 |
| Popis: | cAMP-induced Ca2+ influx in Dictyostelium follows two pathways: a G-protein-dependent pathway where influx is reduced by 50-70% in Galpha2 and Gbeta-negative strains and a heterotrimeric G-protein-independent pathway. Using a pharmacological approach, we found that phospholipase A2 (PLA2) is the target of both pathways. The products of PLA2 activity, arachidonic acid (AA) and palmitic acid, induced Ca2+ influx to a similar extent as cAMP. Half-maximal activation occurred at 3 microM AA and saturation at 10 microM AA. The response to AA was quantitatively similar throughout early differentiation and thus independent of cAMP-receptor concentration. Synergy experiments revealed that cAMP and AA acted through identical pathways. The PLA2-activating peptide, a peptide with sequence similarity to the G-protein beta-subunit, activated Ca2+ influx. The G-protein-independent pathway was sensitive to genistein but not to blockers of protein kinase C and other kinases, suggesting that tyrosine kinase may directly or indirectly activate PLA2 in this case. |
| Databáze: | OpenAIRE |
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