For over seven decades, phosphofructokinase (PFK) has been recognized as a key player in glycolysis – the fundamental metabolic process that breaks down sugar to generate energy. Now, a new study led by the University of Surrey reveals a surprising second function for this ubiquitous enzyme: it actively regulates cell division. This discovery challenges long-held assumptions about PFK and opens new avenues for understanding how cells coordinate growth and proliferation.
The research, published in Nucleic Acids Research, demonstrates that PFK isn’t solely focused on energy production. Specifically, the Pfk2 subunit of PFK can unwind RNA and promote the translation of genes essential for cell division. This finding suggests a sophisticated level of cellular control, where a core metabolic enzyme also acts as a molecular switch governing when cells divide. Understanding this dual role could have implications for fields ranging from cancer biology to developmental biology.
Researchers focused on the yeast Saccharomyces cerevisiae, finding that Pfk2 binds to hundreds of messenger RNAs (mRNAs) within cells. This binding isn’t passive; Pfk2 actively unwinds short, double-stranded RNA segments in a specific direction, effectively boosting the production of proteins that drive cell division. Without Pfk2, yeast cells exhibited slower growth, increased size, and difficulty transitioning from the G1 to S phase of the cell cycle – a critical checkpoint where cells commit to dividing.
Importantly, the study confirmed that this cell division function is independent of PFK’s metabolic role. When researchers reintroduced a version of Pfk2 that was unable to perform glycolysis, the defects in cell division were still rescued. This demonstrates that the enzyme’s ability to regulate cell division isn’t simply a byproduct of its energy-producing function, but a distinct and dedicated capability. “Phosphofructokinase has been studied intensively for its role in metabolism since the 1950s,” explained researchers in the University of Surrey press release. “What we have found is that one of its subunits, Pfk2, also functions as an RNA regulator that helps to coordinate when cells divide. This is not about energy production – we propose that the enzyme acts as a molecular relay, sensing the cell’s energy status and using that information to decide whether to promote growth.”
The discovery builds on existing knowledge of sugar signaling and its influence on cell cycle progression. Research published in Frontiers in Plant Science in March 2024 highlights the importance of sugars, like glucose and sucrose, in regulating the cell cycle, as they are key products of photosynthesis. Sugars act as signaling molecules, remodeling both metabolism and physiology.
The implications of this research extend beyond yeast. Whereas the study focused on Saccharomyces cerevisiae, the underlying mechanisms are likely conserved in other organisms, including humans. Further investigation is needed to determine the extent to which Pfk2 plays a similar role in mammalian cells and whether it could be a potential target for therapeutic interventions. The ability of an enzyme to function in both energy metabolism and cell cycle control represents a previously unappreciated level of cellular integration.
Researchers are now focused on understanding how Pfk2 senses the cell’s energy status and translates that information into decisions about cell division. The enzyme’s role as a “molecular relay” suggests a complex signaling pathway that could be influenced by various factors. Future studies will aim to identify the specific RNA targets of Pfk2 and elucidate the downstream effects of its RNA-unwinding activity. The team also plans to investigate whether disruptions in Pfk2 function contribute to diseases characterized by uncontrolled cell growth, such as cancer.
This discovery underscores the dynamic and interconnected nature of cellular processes. The finding that a well-studied metabolic enzyme possesses a hidden regulatory function highlights the importance of revisiting fundamental assumptions and exploring unexpected roles for established molecules. As our understanding of cellular complexity grows, we can expect to uncover more examples of multifunctional proteins that orchestrate life’s intricate processes.
What are your thoughts on this surprising discovery? Share your comments below, and let’s discuss the potential implications for future research!
