A team of scientists at the University of Cincinnati has shed light on a peculiar evolutionary puzzle involving certain enzymes that are essential to our metabolism, yet have remained somewhat in the shadows of scientific understanding. In a recently published study, the researchers have traced the evolutionary origins of what appear to be non-functional enzyme components, which might actually play a significant, albeit enigmatic, role in our cells.
As reported by the University of Cincinnati’s news service, the focus of the study was on the enzyme complex phosphoribosyl pyrophosphate synthetase (PRPS), which boasts four distinct proteins: PRPS1, PRPS2, and two PRPS-associated proteins, AP1 and AP2. While PRPS1 and PRPS2 have been well-studied due to their standalone catalytic abilities, AP1 and AP2 have garnered less attention because they seem to lack these catalytic functions. Bibek Karki, the first author of the study and a doctoral cancer biology student, spoke on the significance of the findings. He noted: “In a way, AP1 and AP2 have been like ‘zombie’ enzymes. They exist, but they don’t seem to have catalytic properties.”
Despite the apparent lack of function in isolation, the existence of AP1 and AP2 across various species suggests an important evolutionary advantage. Genes that persist over time typically provide a beneficial trait for the organism's survival, thus raising the question of why these seemingly redundant enzymes are conserved in nature. “If a gene is evolutionarily conserved, it means it’s repeatedly favoured by nature,” Karki explained in a University of Cincinnati release. “That indicates it must be doing something important; otherwise, nature would have let it go.” This hints at a critical, yet mysterious, role for AP1 and AP2 within the PRPS enzyme function.
The implications of such findings extend beyond mere academic curiosity. Understanding the full range of functions and interactions within this enzyme complex could lead to advancements in medical research and treatments for conditions stemming from metabolic disorders. The endeavor continues to unravel the functions of AP1 and AP2, as this study encourages a closer examination of the potentially overlooked roles that these proteins might play.
You can read more about this research in the detailed report on the University of Cincinnati’s website.
