Tokyo, Japan – Researchers in Tokyo, Japan have uncovered a fascinating memory system within cells that helps them remember when their parent cells underwent challenging division processes. This discovery sheds light on how individual cells store crucial information related to cell division, particularly in the context of DNA damage and cancer risks.
Cell division is tightly regulated in multicellular organisms to prevent uncontrolled growth, a hallmark of cancer development. However, problems with specific stages of division, such as DNA replication and chromosome segregation, can lead to mutations. To ensure proper division, cells have built-in checkpoints to verify that each step is completed accurately. Despite passing these checkpoints, cells may still face issues if certain processes take too long, like in the case of mitosis.
The researchers found that prolonged mitosis can lead to chromosome damage, prompting cells to halt division to prevent potential problems in the future. This phenomenon, termed a “mitotic stopwatch,” was initially observed in retinal cells but was later discovered to be a general response to delayed mitosis across various cell types. The mechanism behind this stopwatch involves a complex of proteins, including the well-known tumor suppressor p53.
During mitosis, p53 forms a complex with two other proteins, USP28 and p53BP1, only if the process takes longer than usual. This complex remains stable and can be passed on to daughter cells after division, where it helps regulate cell growth and prevent further divisions if needed. Disruption of this protein complex, triggered by specific kinases, can result in faulty cell division and increase the risk of tumor formation.
The study highlights the intricate ways in which individual cells can retain memories of past cell division challenges. The mitotic stopwatch represents just one of the many memory storage systems within cells, each contributing to the overall maintenance of cellular integrity. By understanding these mechanisms, scientists can gain insights into how cells safeguard themselves against potential threats like cancer development.
Overall, this research offers a fascinating glimpse into the internal workings of cells and how they remember critical events related to their division processes. This discovery opens up new avenues for exploring the complexities of cellular memory systems and their implications for health and disease.