Vitellogenesis in the fruit fly, Drosophila melanogaster: antagonists demonstrate that the PLC, IP3/DAG, PK-C pathway is triggered by calmodulin.
In Drosophila melanogaster M. (Diptera: Drosophilidae), a phospholipase-C to proteininase-C signal cascade leads to the endocytic uptake of yolk precursor molecules. The data suggest that D. melanogaster has a phospholipase-C/proteinkinase-C signaling pathway similar to that previously shown to be required for vitellogenesis in the milkweed bug, Oncopeltus fasciatus Dallas (Hemiptera: Lygaeidae). Calmodulin, derived from epithelial cells and transported to the oocytes via gap junctions, may trigger this pathway. To investigate this, a series of known antagonists to various elements of the pathway were used. W-7 (which prevents calmodulin binding to phospholipase-C), U-73122 (which prevents activation of phospholipase-C), verapamil (which blocks Ca(2+) release by IP3), HAG (which blocks diacylglycerol), and staurosporine (which inactivates proteinkinase-C) were each shown to inhibit endocytosis, thereby blocking formation of nascent yolk spheres.
Department of Biology, West Chester University, West Chester, PA 19383, United States.
Bethany J
BJ
Brubaker-Purkey
Richard I
RI
Woodruff
D000818:Animals; D002147:Calmodulin / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000502:physiology*; D004705:Endocytosis; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D017629:Gap Junctions / Q000378:metabolism; D020062:Heteroptera / Q000502:physiology; D008856:Microscopy, Fluorescence; D009865:Oocytes / Q000502:physiology*; D015398:Signal Transduction; D014818:Vitellogenesis; D014819:Vitellogenins
D002147:Calmodulin; D014819:Vitellogenins