Filament assembly by the liver phosphofructokinase‐1, the “gatekeeper” of glycolysis

Abstract

Despite abundant knowledge of the regulation and biochemistry of glycolytic enzymes, we have limited understanding on how they are spatially organized in the cell. Emerging evidence indicates that metabolic enzymes from diverse pathways can assemble into filaments. We show that the liver isoform of glycolytic “gatekeeper” enzyme phosphofructokinase‐1 (PFKL), which catalyzes the step committing glucose to breakdown, forms filaments in vitro and dynamic punctae in cells. Recombinant PFKL, but not platelet or muscle isoforms, assembles into filaments in a concentration‐, substrate‐, and tetramer‐dependent manner. Filaments are apolar and made of stacked tetramers oriented with exposed catalytic sites positioned along the edge of the polymer as determined by negative‐stain electron micrographs. Quantified live‐cell imaging shows PFKL‐EGFP appears as dynamic puncta that are enriched at discrete locations at the plasma membrane. These findings reveal a new behavior of a key glycolytic enzyme with insights on spatial organization and isoform‐specific glucose metabolism in cells. Support or Funding Information West Virginia University Start up funds