The inositol phosphate/diacylglycerol signalling pathway in Trypanosoma cruzi.
Using [32P]Pi and [3H]inositol as precursors, we have detected the presence of phosphatidylinositol, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate, and their derivatives inositol phosphate, inositol 1,4-bisphosphate and inositol 1,4,5-trisphosphate respectively, in Trypanosoma cruzi epimastigotes. Using digitonin-permeabilized cells it was possible to detect a stimulation in the formation of inositol 1,4,5-trisphosphate and inositol 1,4-bisphosphate as well as an increased generation of diacylglycerol in the presence of 1 mM-CaCl2. These results are consistent with the operation of a functional inositol phosphate/diacylglycerol pathway in T. cruzi, and constitute the first demonstration of the presence and activation of this pathway in a parasitic protozoan. These results also indicate that this pathway is conserved during evolution from lower to higher eukaryotic organisms.
Docampo
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Department of Veterinary Pathobiology, University of Illinois, Urbana 61801.
Pignataro
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D000818:Animals; D001345:Autoradiography; D002118:Calcium / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004075:Diglycerides / Q000378:metabolism*; D007294:Inositol / Q000378:metabolism; D007295:Inositol Phosphates / Q000302:isolation & purification / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D010716:Phosphatidylinositols / Q000302:isolation & purification / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D015398:Signal Transduction; D014316:Tritium; D014349:Trypanosoma cruzi / Q000502:physiology*
D004075:Diglycerides; D007295:Inositol Phosphates; D010710:Phosphates; D010716:Phosphatidylinositols; D010761:Phosphorus Radioisotopes; D014316:Tritium; D007294:Inositol; D002118:Calcium