Journal Article

Compartmentation prevents a lethal turbo-explosion of glycolysis in trypanosomes

Haanstra, Jurgen R, Kessler, Peter, van Tuijl, Arjen, Reijnders, Willem, Michels, Paul A.M, Westerhoff, Hans V, Parsons, Marilyn, Bakker, Barbara M

2008

Overview

ATP generation by both glycolysis and glycerol catabolism is autocatalytic, because the first kinases of these pathways are fuelled by ATP produced downstream. Previous modeling studies predicted that either feedback inhibition or compartmentation of glycolysis can protect cells from accumulation of intermediates. The deadly parasite Trypanosoma brucei lacks feedback regulation of early steps in glycolysis yet sequesters the relevant enzymes within organelles called glycosomes, leading to the proposal that compartmentation prevents toxic accumulation of intermediates. Here, we show that glucose 6-phosphate indeed accumulates upon glucose addition to PEX14 deficient trypanosomes, which are impaired in glycosomal protein import. With glycerol catabolism, both in silico and in vivo, loss of glycosomal compartmentation led to dramatic increases of glycerol 3-phosphate upon addition of glycerol. As predicted by the model, depletion of glycerol kinase rescued PEX14-deficient cells of glycerol toxicity. This provides the first experimental support for our hypothesis that pathway compartmentation is an alternative to allosteric regulation.

• Publisher: National Academy of Sciences,National Acad Sciences
• Subject: Adenosine triphosphatase / adenosine triphosphate / Allosteric regulation / Animals / ATP / Biochemistry / Biological Sciences / Catabolism / Catalysis - drug effects / Cell Compartmentation - drug effects / Cell lines / Cytosol / Enzymes / glucose / Glucose - pharmacology / glucose 6-phosphate / Glucose-6-Phosphate - metabolism / glycerol / Glycerol - toxicity / glycerol kinase / Glycerol Kinase - deficiency / Glycolysis / Glycolysis - drug effects / Glycosylation / Kinases / Membrane Proteins - metabolism / Microbodies / Microbodies - drug effects / Microbodies - metabolism / Modeling / Mutation - genetics / Parasites / Parasitic protozoa / Phenotype / protein transport / Protein Transport - drug effects / Proteins / Protozoan Proteins - metabolism / Pyruvic Acid - metabolism / RNA Interference - drug effects / Subcellular Fractions - drug effects / Subcellular Fractions - enzymology / Toxicity / Trypanosoma brucei / Trypanosoma brucei brucei - drug effects / Trypanosoma brucei brucei - enzymology / Trypanosoma brucei brucei - metabolism / Trypanosome