If aging and cancer were dancing a duet, telomerase would be the orchestra. This enzyme is responsible for rebuilding the telomeres at the ends of chromosomes, and without it, stem cells would age and the growth potential of cells would end. The problem: in about 90% of cancer types, telomerase is forcefully activated and allows cancer cells to divide indefinitely. An international team that published its findings in Science in March 2026 presents for the first time a complete 3D map of the enzyme in yeast, and within it a surprising discovery: a surface structure we did not know about, which may in the future be a target for cancer drug research.
Why is telomerase so important?
Telomeres, repetitive DNA sequences at the ends of chromosomes, shorten with each cell division. When they are worn down enough, the cell loses its ability to divide (senescence) or dies (apoptosis). This is a natural process that protects us from cancer: a cell that has grown too much meets its fate.
But there is a flaw in this defense. In 90% of cancer types, the TERT gene (which produces telomerase) is reactivated. Cancer cells can lengthen their telomeres without limit, becoming immortal. This replicative immortality is one of the "Hallmarks of Cancer" described by Hanahan and Weinberg in 2000.
The problem: hiding the complete picture
For decades, scientists documented telomerase in parts: only the protein component, only the RNA, only part of the complex. The reason: the enzyme is complex, its parts are flexible, and in an electron microscope it moves and disperses. You cannot develop a targeted drug if you do not see the full shape.
Structural knowledge of telomerase remained partial for years: individual components were mapped separately, but no one succeeded in revealing the complete complex, TERT (the protein), the RNA, and the auxiliary proteins, all together. The new study is the first to present the complete structure of the telomerase holoenzyme, in this case in yeast.
The breakthrough: international collaboration
The team, in a collaboration between the University of Montreal, the University of Sherbrooke, and the MRC Laboratory of Molecular Biology in Cambridge, UK, used Cryo-EM (cryogenic electron microscopy). They froze the enzyme in ultra-thin ice, photographed it from millions of different angles, and calculated the complete shape at near-atomic resolution. The research was led by Hongmiao Hu, the first author from the MRC Laboratory, and Thi Hoang Duong Nguyen, the senior researcher from the MRC Laboratory, together with Pascal Chartrand from the University of Montreal.
To simplify the experiment, they chose to work with telomerase from yeast (Saccharomyces cerevisiae) instead of human. Yeast is less complex and easier to produce its enzyme in the lab. It is important to emphasize: the structure of yeast telomerase differs significantly from that of human and vertebrate telomerase, but the core mechanism is conserved (for example, Est3 in yeast is the homolog of human TPP1). This was the step that enabled the revolution.
The discovery: a secret zinc finger
When the structure was revealed, the team identified something no one had described before: a zinc finger within telomerase. Zinc fingers are structural motifs in proteins that precisely grasp DNA or RNA. Until now, we did not know that telomerase uses one.
The surprising discovery: this finger grasps part of the telomerase RNA and thereby stimulates the enzyme's activity. When the team created a mutation in the finger, telomerase activity nearly disappeared.
"Our research indicates that this zinc finger binds to part of the telomerase RNA, thereby stimulating the enzyme's activity," said Pascal Chartrand from the University of Montreal.
Est3: the scaffold holding everything together
The team also discovered the true role of Est3, a protein that everyone knew about but did not understand its function. In the new picture, Est3 is a molecular scaffold that connects all the components of telomerase and maintains its solid structure. Without it, the enzyme disintegrates.
This is also a promising drug target: if Est3 can be disrupted, the entire telomerase can be disabled, without harming other proteins in the cell.
Why is this important for cancer?
With this knowledge, researchers can in the future develop drugs that do one of two things:
- Block the zinc finger: reduces telomerase activation. In cancer cells that rely on telomerase, this is disastrous. In healthy cells, the effect is minimal because they use telomerase to a tiny extent.
- Disrupt Est3: a drug that dismantles the telomerase structure.
It is important to clarify the context: this is basic research in structural biology, on a yeast enzyme. There is currently no timeline for drug development, and any treatment that may arise from this is many years away and not yet planned. The value of the research is that it provides for the first time the structural "map" that will enable future design of targeted molecules.
Implications for anti-aging
The other side of the coin: aging. Drugs that suppress telomerase help against cancer but can accelerate aging (less cell renewal). Drugs that activate telomerase can slow aging but risk cancer.
A deeper structural understanding opens up in the future the theoretical possibility of tissue-specific activation. A drug that activates telomerase only in specific stem cells (e.g., in the skin or blood), without reaching other cells, could provide the benefits without the risk. This is a distant vision, not a promise.
Broader context
This is an example of what scientists in the field call structure-based drug design. Instead of searching for drugs randomly, you look at the drug target in 3D and design a molecule that fits precisely. Most new drugs since 2010 have been developed this way. Now, finally, there is an initial structural tool to think about drugs against telomerase, even if the path is still long and studies on the human enzyme are needed.
This discovery lays the foundation for decades of drug research. Until now, researchers tried to develop telomerase inhibitors without a complete structural picture, and many efforts failed. Now, at least in yeast, there is a map.
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