Study Reveals Dual Role Of Pfk Enzyme In Metabolism And Cell Cycle Progression

A metabolic enzyme studied for complete 7 decades has a hidden 2nd usability - it tin unwind RNA and beforehand compartment rhythm progression, an further usability beyond its domiciled successful power production, according to a caller study led by nan University of Surrey.

Phosphofructokinase (PFK) is nan 'gatekeeper' of glycolysis, nan ancient and evolutionarily conserved metabolic pathway that breaks down sweetener to make energy. In nan yeast Saccharomyces cerevisiae, PFK is made up of 2 subunits - Pfk1 (α) and Pfk2 (β). While some person agelong been understood arsenic metabolic partners, nan Surrey-led squad has discovered that Pfk2 possesses an wholly abstracted capability. It binds hundreds of messenger RNAs (mRNA) wrong cells, unwinds short double-stranded RNA successful a circumstantial direction, and actively promotes nan translator of genes that thrust compartment division.

Published successful Nucleic Acids Research, nan study shows that without Pfk2, yeast cells turn much slowly, go importantly larger and struggle to advancement from nan G1 to S shape of nan compartment rhythm - a captious modulation constituent wherever cells perpetrate to division. Crucially, reintroducing a type of Pfk2 that cannot execute glycolysis still rescued these defects, confirming that nan enzyme's domiciled successful compartment section is independent of its metabolic function.

Professor André Gerber, corresponding writer of nan study from nan University of Surrey's School of Biosciences, said:

"Phosphofructokinase has been studied intensively for its domiciled successful metabolism since nan 1950s. What we person recovered is that 1 of its subunits, Pfk2, besides functions arsenic an RNA regulator that helps to coordinate erstwhile cells divide. This is not astir power accumulation - we propose that nan enzyme acts arsenic a molecular relay, sensing nan cell's power position and utilizing that accusation to determine whether to beforehand growth."

The investigation squad utilized a operation of RNA sequencing, biochemical assays (laboratory tests to study molecular behaviour) and proteomics (large-scale study of proteins) to build their case. They identified complete 800 mRNAs that Pfk2 binds successful surviving cells, galore of which codification for proteins progressive successful controlling nan mitotic compartment rhythm (the process by which a compartment divides into two). Using tests that usage ray signals to way RNA strands being pulled isolated successful existent time, nan investigation squad showed that Pfk2 - but not Pfk1 - tin unwind short double-stranded RNA molecules pinch a circumstantial directionality, a usability usually associated pinch dedicated RNA helicase enzymes (specialised proteins whose superior occupation is to unwind RNA).

Polysome profiling (a method that separates compartment contents to uncover which mRNAs are actively being made into proteins) revealed that successful cells lacking Pfk2, mRNAs for captious compartment rhythm regulators - including nan G1 cyclin CLN3 (a macromolecule that triggers nan commencement of compartment division) and nan spindle checkpoint macromolecule BUB3 (a macromolecule that ensures chromosomes are correctly separated) - shifted dramatically distant from ribosomes, indicating they were nary longer being efficiently translated into proteins. Proteomics confirmed reduced levels of compartment rhythm proteins successful Pfk2 deletion mutants (cells wherever nan cistron coding for Pfk is removed).

The squad proposes a "molecular relay switch" model. When cellular power is low, PFK adopts its enzymatically progressive authorities and focuses connected glycolysis. When power is abundant, Pfk2 shifts to a low-activity style that enhances its expertise to hindrance and unwind RNA, promoting nan translator (production of proteins from RNA instructions) of compartment rhythm genes and enabling compartment division. This creates a nonstop molecular nexus betwixt a cell's metabolic authorities and its determination to proliferate.

Waleed Albihlal, first writer of nan study and a interrogator astatine nan University of Surrey, said:

"For decades, PFK has been described successful each biochemistry textbook arsenic a unifunctional enzyme acting solely successful glycolysis. The find of this dual usability of PFK opens up caller avenues to beforehand our knowledge of captious compartment functions. This could, for instance, let america to amended understand illness involving misregulation of compartment rhythm and lead to improvement of caller therapeutics. Furthermore, this find raises an important mobility - really galore much hidden functions are location successful different enzymes that request to beryllium discovered?"

The investigation was funded by nan Biotechnology and Biological Sciences Research Council (BBSRC), Cancer Research UK and nan Engineering and Physical Sciences Research Council (EPSRC). International collaborators included teams astatine nan Cancer Research UK Scotland Institute, nan University of Osnabrück, nan University of Basel and Ulm University.