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InsP3 and Ins(1,3,4,5)P4 act in synergy to stimulate influx of extracellular Ca2+ in Xenopus oocytes.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Delisle, Susan Pittet, Didier |
| Copyright Year | 1992 |
| Abstract | To investigate the role of D-myo-inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P4] in the regulation of Ca2+ influx, we injected inositol phosphates into Xenopus oocytes and measured Ca(2+)-gated Cl- current to assay intracellular free Ca2+ concentration ([Ca2+]i). To assess Ca2+ influx, we removed extracellular Ca2+ or added the inorganic Ca2+ channel blocker Mn2+ to the extracellular bath and measured the resulting change in Cl- current. Ins(1,3,4,5)P4 did not cause Ca2+ influx when injected alone or when preceded by an injection of Ca2+. In contrast, Ins(1,3,4,5)P4 stimulated Ca2+ influx when injected after the poorly metabolized inositol trisphosphate (InsP3) analogues D-myo-inositol 1,4,5-trisphosphorothioate [Ins(1,4,5)P3S3] or D-myo-inositol 2,4,5-trisphosphate [Ins(2,4,5)P3]. These results indicate that Ins(1,3,4,5)P4 is not sufficient to stimulate Ca2+ influx but acts in synergy with InsP3s to cause Ca2+ influx. We also studied the effect of Ca2+ influx on the immediate metabolism of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] in single oocytes. Ca2+ influx shunted the metabolism of Ins(1,4,5)P3 toward the formation of Ins(1,3,4,5)P4 and away from D-myo-inositol 1,4-bisphosphate [Ins(1,4)P2]. These results suggest that there is a positive feedback regulatory mechanism in which Ca2+ influx stimulates Ins(1,3,4,5)P4 production and Ins(1,3,4,5)P4 stimulates further Ca2+ influx. |
| Starting Page | 1 |
| Ending Page | 41 |
| Page Count | 41 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://purehost.bath.ac.uk/ws/portalfiles/portal/6017818/Potter_InsP3.pdf |
| PubMed reference number | 1377444v1 |
| Volume Number | 262 |
| Issue Number | 6 |
| Part | 1 |
| Journal | The American journal of physiology |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase Calcium ion Chloride Ion Chloride-Bicarbonate Antiporters Inositol 1,4,5-Trisphosphate Inositol Phosphates Manganese Cation (2+) Metabolic Process, Cellular inorganic phosphate inositol-1,3,4,5-tetrakisphosphate |
| Content Type | Text |
| Resource Type | Article |
