Vitellogenesis in the Fruit Fly,Drosophila melanogaster:Antagonists Demonstrate that the PLC, IP₃/DAG, PK-C Pathway is Triggered by Calmodulin

Abstract

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 Ca2+ 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.

Virulent Diuraphis noxia Aphids Over-Express Calcium Signaling Proteins to Overcome Defenses of Aphid-Resistant Wheat Plants

“…Experiments were conducted to inhibit PLCγ1 in D . noxia biotype 2 aphids fed U-73122, a PLCγ1 inhibitor [ 52 , 53 ] and a control diet containing an equal concentration of U-73343, an inactive (non-inhibitory) form of U-73122. The concentration of U-73122 causing minimal inhibition of aphid feeding was determined using serial dilutions from 0.17mM to 0.025mM final concentration in an artificial aphid diet developed by Febvay et al [ 54 ] using 2mM stock.…”

Asian Citrus Psyllid Expression Profiles Suggest Candidatus Liberibacter Asiaticus-Mediated Alteration of Adult Nutrition and Metabolism, and of Nymphal Development and Immunity

“…The ACP nymphal genes found to be overexpressed by greater than 10-fold were calmodulin, hedgehog, survivin, talin 2 and wnt. Such genes are known to be activated during energy-intensive processes including development, cell and tissue differentiation, growth, and molting in nymphs [ 55 – 58 ]. In addition to wnt, twenty-one other contigs were identified in the Hedgehog signaling pathway, constituting 85% of the predicted pathway members ( S1 Table ).…”

Transcriptional profiling and physiological roles of Aedes aegypti spermathecal-related genes

“…Additionally, Ca 2+ ionic channels play an important role in vitellogenin (Vg) uptake in insects, including Ae. aegypti [51,52]. Any alteration in this ionic balance is likely to result in egg Vg storage reduction and impairment of egg development.…”