Dynamics of phosphofructokinase condensation are regulated by metabolic and redox cues

Abstract

Condensation of phosphofructokinase, the rate-limiting enzyme of glycolysis, into granules has been observed across species and in various stress conditions. However, it remains unclear what mechanisms govern this process. Here, we show that the two subunits of yeast phosphofructokinase, Pfk1 and Pfk2, assemble into granules even in the absence of exogenous stress, challenging the notion that PFK condensation in yeast is restricted to quiescent or stressed cells. While phosphofructokinase granules are predominant in replicatively aged cells, they are independent of cell division and can form before or after cells cease dividing. We further demonstrate that both subunits can co-localise to the same granules and that Pfk2 requires the disordered N-terminus of Pfk1 for assembly. Strikingly, phosphofructokinase granules are largely absent in cells engaged in respiration or lacking respiratory capacity, but their formation is strongly induced during the metabolic transition from fermentation to respiration. This suggests that phosphofructokinase condensation is tightly linked to the metabolic strategy of the cell. Moreover, we find that reactive oxygen species signaling, mediated by superoxide dismutase 1 (Sod1), modulates phosphofructokinase granule formation, as cells deficient in Sod1 exhibit impaired granule assembly. Overall, our results indicate that phosphofructokinase condensation is a dynamic process regulated by metabolic and redox cues.