Research conducted at the University of Geneva has revealed that even a minor surplus in the production of tubulin—a protein essential for cell structure—is enough to disrupt tissue organization, highlighting the critical need for strict regulation of this protein’s levels.
For cells to function properly, they must produce the right amount of each protein. This is a delicate balance: both a deficiency and an excess can impair vital cellular processes. A team from the University of Geneva has demonstrated that even a slight excess of tubulin—the protein that assembles into microtubules, the cell’s internal framework—is sufficient to compromise tissue architecture and reduce cell viability. The study, published in the journal Nature Communications, underscores that the quantity of a protein is just as important as its function.
Microtubules, built from tubulin, form the cell’s internal skeleton. They help cells maintain their shape, transport molecules, divide, and stay firmly attached to neighboring cells. Unlike rigid structures, microtubules are constantly assembling and disassembling, adapting to the cell’s changing needs. This dynamic behavior is directly influenced by the amount of tubulin available.
For over forty years, biologists have known that cells possess a mechanism that slows down tubulin production when its levels become too high. However, the biological purpose of this regulatory pathway remained unclear. To address this question, a group led by Ivana Gasic, a professor in the Department of Molecular and Cellular Biology at the University of Geneva’s Faculty of Science, used three-dimensional spheroids. “These 3D cell culture models behave like tissues and replicate cell-to-cell interactions much more accurately than conventional 2D cultures,” she explains. “Our findings show that cells regulate not only which proteins they produce, but also their quantities with remarkable precision.”
Using advanced microscopy techniques, the researchers examined spheroids containing cells that produced 10-20% more tubulin than usual. “One might expect that more of this protein would strengthen the cytoskeleton, but the opposite is true,” says study co-author Ana Coelho de Almeida. “The excess tubulin makes microtubules abnormally stable and slows their ability to reorganize. As a result, cells can no longer adapt their architecture to environmental constraints.”
The consequences quickly extend beyond individual cells. Proteins responsible for cell adhesion and attachment to the extracellular matrix no longer position themselves correctly. Cellular contacts weaken, tissue architecture gradually deteriorates, and cell viability declines. “Our results indicate that cells regulate not only which proteins they produce, but also their quantities with astonishing accuracy. In the case of tubulin, even a slight excess is enough to disrupt tissue organization. This reveals a fundamental principle of cell biology,” adds Ana Coelho de Almeida.
Beyond advancing our understanding of microtubule biology, this study establishes protein quantity control as a key mechanism for maintaining cellular homeostasis. This regulatory pathway is particularly relevant because microtubules are already targeted by several anticancer drugs, including paclitaxel, which stabilizes microtubules to prevent tumor cell division. In the future, a deeper understanding of this pathway may pave the way for new therapeutic strategies aimed at modulating tubulin levels or complementing existing treatments that target microtubule dynamics.
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