Within every cell, a delicate balance constantly exists between constructing new structures and safeguarding genetic information. However, researchers in Madrid have uncovered a remarkable paradox: a molecule essential for cell division can simultaneously disable one of the genome's most crucial preservation mechanisms. The study, published in July 2026 in Biochimica et Biophysica Acta, reveals that an intermediate product of cholesterol synthesis—mevalonate diphosphate—inhibits the enzyme PrimPol, which helps cells continue DNA replication even when significant obstacles arise.
Each time a cell prepares to divide, it faces one of biology's most complex tasks: flawlessly replicating its entire genome. While this process typically proceeds smoothly, if the replication machinery encounters damage or difficult DNA regions, the enzyme PrimPol activates. It can be likened to a roadside assistance service: it creates a new starting point, enabling the copying mechanism to bypass the obstruction and continue its journey, thus preventing the genome from remaining incomplete.
It is precisely this crucial rescue mechanism that mevalonate diphosphate—an intermediate molecule in the cholesterol synthesis pathway—has been found to deactivate.
The team led by María Martínez-Jiménez utilized fluoromevalonate to induce the accumulation of mevalonate diphosphate. Almost immediately, cells became 'stuck' in the DNA replication phase. Signals of replicative stress were activated, and signs of genome damage emerged within them. However, when researchers blocked mevalonate formation using the drug lovastatin, this effect virtually vanished.
The results of molecular modeling proved particularly interesting. They demonstrated that mevalonate diphosphate does not act indirectly; instead, it binds directly to PrimPol, hindering the enzyme from performing its function. Essentially, this small molecule occupies a critically important site on the protein, thereby preventing it from initiating DNA re-synthesis at replication arrest points.
This discovery indicates that the cholesterol synthesis pathway is not merely a biochemical conveyor belt for producing membrane components. Its intermediate products are capable of directly interfering with processes responsible for genome stability. This creates a peculiar cellular paradox: while preparing for division, the cell can simultaneously disable a mechanism that helps safely complete the replication of its own DNA.
If PrimPol ceases to function, replication forks increasingly stall, DNA damage accumulates, and the cell becomes unable to complete division. This type of genomic instability is considered a key factor in tissue aging and the development of oncological diseases. Therefore, the connection between metabolism and replication mechanisms might be significantly deeper than previously assumed.
As the research has thus far only been conducted on cellular models, it is premature to discuss the mechanism's impact within the human body. Nevertheless, the study offers a completely new perspective on cholesterol metabolism. It suggests that its intermediate products may function not merely as building blocks for the cell, but also as unique regulators capable of determining when to proceed with division and when to halt it.
Such unexpected connections between metabolism and DNA protection could form the basis for future research into aging and oncology, fields where maintaining genome integrity remains one of modern biomedicine's primary objectives.
