How much (ATP) does it cost to build a trypanosome? A theoretical study on the quantity of ATP needed to maintain and duplicate a bloodstream-formTrypanosoma bruceicell

Abstract

AbstractATP hydrolysis is required for the synthesis, transport and polymerization of monomers for macromolecules as well as for the assembly of the latter into cellular structures. Other cellular processes not directly related to synthesis of biomass, such as maintenance of membrane potential and cellular shape, also require ATP. The unicellular flagellated parasiteTrypanosoma bruceihas a complex digenetic life cycle. The primary energy source for this parasite in its bloodstream form (BSF) is glucose, which is abundant in the host’s bloodstream. Here, we made a detailed estimation of the energy budget during the BSF cell cycle. As glycolysis is the source of most produced ATP, we calculated that a single parasite produces 6×1011molecules of ATP/cell cycle. Biomass production accounts for ∼62% of the total energy budget, with translation being the most expensive process. Flagellar motility, variant surface glycoprotein recycling, transport and maintenance of transmembrane potential account for less than 30% of the consumed ATP. Finally, there is still ∼9% available in the budget that is being used for other cellular processes of unknown cost. These data put a new perspective on the assumptions about the relative energetic weight of the processes a BSF trypanosome undergoes during its cell cycle.Abstract ImportanceCells use ATP as the main energy currency for the synthesis, organization and maintenance of their macromolecules and cellular structures, in order to stay alive and proliferate. For this purpose, ATP is produced from external nutrients, and is spent by cells in the many processes that are necessary for maintenance and building up new cells. Despite its relevance and the impressive quantity of biological data available, very little is known about how much ATP is required for maintaining and duplicating a cell. In this paper, we present a calculation on how much of the ATP produced by catabolism of the nutrient glucose is used to energize the different processes known to occur during the cell cycle of the infective form of the trypanosomatid parasite that causes human sleeping sickness, the bloodstream form ofTrypanosoma brucei.