Alzheimer’s-Linked Protein Found To Play Key Role in Cell Division

All processes such as wound healing, hair growth, and the replacement of old cells with new ones depend on cell division. During this process, chromosomes inside the cell must be evenly divided between two daughter cells. Even slight errors can lead to cellular abnormalities.

A research team at POSTECH has recently uncovered new clues suggesting that a protein called tau plays an important role in this highly regulated process. The findings were published in the international journal Nature Communications.

Tau is a protein frequently mentioned in Alzheimer’s disease research. In neurons, it stabilizes microtubules, which are slender structural components inside cells. In the brains of Alzheimer’s patients, however, tau is known to aggregate abnormally. More recently, tau has been reported to gather various molecules within the cell to form small structures known as condensates, but the significance of its interaction with DNA has remained unclear. The research team focused on this unexplored area.

During cell division, chromosomes are captured by bundles of microtubules called spindle microtubules, which pull them apart into two daughter cells. For this process to proceed correctly, chromosomes and spindle microtubules must be precisely connected. The researchers used single DNA molecules to investigate whether tau assists in this connection.

They found that tau binds to DNA to form condensates, moves freely along DNA strands, and pulls nearby strands together.

Using high-resolution fluorescence imaging, the team further confirmed that tau–DNA condensates act as attachment points that capture microtubules. This interaction was observed not only in in vitro experiments but also in living cells.

The researchers also found that phosphorylation, a chemical modification of tau, affects this process. When tau modified in a manner observed in Alzheimer’s disease was expressed in cells, abnormalities were detected in chromosomes that failed to align properly during cell division. This suggests that even subtle changes in tau can affect the accuracy of the entire cell division process.

The team expects that this discovery will provide new perspectives not only for research on infertility and congenital disorders, but also for studies on neurodegenerative diseases, including Alzheimer’s disease.

Professor Minju Shon, who led the study, said, “This work suggests that tau can directly interact not only with microtubules but also with DNA, potentially linking the two structures. It also shows that tau may be involved in the early stages when chromosomes first establish connections with spindle microtubules during cell division."