Araiza-Olivera D, Chiquete-Felix N, Rosas-Lemus M, Sampedro JG, Pena A, Mujica A, Uribe-Carvajal S

In the Saccharomyces cerevisiae glycolytic pathway, eleven enzymes catalyze the stepwise conversion of glucose to 2 molecules of ethanol plus 2 CO2 s. In the highly crowded cytoplasm, this pathway would be very inefficient if it were dependent on substrate/enzyme diffusion. Therefore, the existence of a multienzymatic glycolytic complex has ...

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been suggested. This complex likely uses the cytoskeleton to stabilize the interaction of the different enzymes. Here, the role of filamentous actin (F-actin) in the stabilization of a putative glycolytic metabolon is reported. Experiments were performed in isolated-enzyme/actin mixtures, in cytoplasmic extracts and in permeabilized yeast cells. Polymerization of actin was promoted with phalloidin or inhibited with cytochalasin D or latrunculin. The polymeric, filamentous F-actin, but not the monomeric, globular G-actin, stabilized both the interaction of isolated glycolytic-pathway enzyme mixtures and the whole fermentation pathway, leading to higher fermentation activity. The associated complexes were resistant against inhibition, either by viscosity (promoted by the disaccharide trehalose) or by inactivation (by specific enzyme antibodies). In S. cerevisiae a glycolytic metabolon seems to assemble in association with F-actin. In this complex fermentation activity is enhanced and enzymes are partially protected against inhibition by trehalose or by antibodies. This article is protected by copyright. All rights reserved.

Date: Jun. 14, 2013

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