In the Yeast Saccharomyces Cerevisiae Actin Stabilizes a Glycolytic Pathway Enzyme Complex

Abstract

Metabolic pathway enzymes may associate into supramolecular complexes increasing efficiency and protecting each other from inhibitors and physical stress. The eukaryotic cytoplasm is a concentrated, highly organized mesh of fibers, macromolecules and solutes. Here, the associations of specific proteins would result in intermediary channeling. In addition, enzymes in complexes are probably protected against inhibition during the stress response, when compatible solutes rise. However, detection of complexes is difficult due to the weak nature of enzyme associations; this difficulty was circumvented by adding F-actin in order to stabilize association and further modify activity and stability of the complexed enzymes. Polymeric F-actin, but not the monomeric G-actin stabilized glycolytic enzyme complexes and promoted protection against inhibition by either trehalose or by specific anti-enzyme antibodies. The association of specific enzymes and even the whole fermentation pathway were stabilized by F-actin, producing a functional pathway that resisted inhibition by either trehalose or by antibodies.