In biology, cyclins are key proteins in the cell cycle. They control the progression of cells in the cell cycle by activating cell cycle-dependent kinases (CDKs). The discovery of these molecules not only promoted the advancement of the scientific community, but also gave birth to an interesting story about their naming, which is a beautiful memory that combines scientific enthusiasm and personal interest.
The discovery of cyclins dates back to 1982, by biologist R. Timothy Hunt, who was studying the cell cycle of sea urchins. Hunt revealed in an interview with the media, "I created this name because I loved cycling at the time." This is obviously a humorous expression, but it has become an indispensable term in the biological world today.
"Actually, the name is a joke. It comes from the fact that I like cycling very much, and these cyclins exist just like they appear and disappear from time to time during the cell cycle."
Initially, Hunt did not foresee that the name would become so important. However, as the research deepened, the importance of cyclins in the cell cycle gradually emerged, which made the name particularly scientifically appropriate.
The name cyclins originates from the fact that their concentration in the cell cycle fluctuates periodically over time. These fluctuations are caused by gene expression and the ubiquitin-mediated proteasome pathway, which in turn drive changes in CDK activity.
Cyclins themselves have no enzymatic activity, but they can combine with CDK to form a complex, thereby initiating various processes of the cell cycle. These cyclins can be divided into four categories according to the stage of their action in the cell cycle:
Such classification not only helps scientists better understand the behavior of the cell cycle, but also provides important insights into how cells regulate growth and division. Particularly worth mentioning are G1/S cyclins. When cells enter S phase, their concentration will rise rapidly. This change directly affects the DNA replication process.
With in-depth research on cyclins, scientists have discovered that they are closely related to various types of cancer. For example, the D-type cyclin (ORF72) encoded by Kaposi sarcoma herpesvirus (KSHV) binds to CDK6 and may promote the development of KSHV-related cancers.
In the cell cycle, there are many different cyclins, which play different roles at different stages. Although some cyclins are "orphan" types, that is, no specific CDK partners have yet been found, they still play important roles in cell growth and division. For example, cyclin A plays a key role in promoting the detachment of microtubules from kinetochores, ensuring correct chromosome segregation, which is required for normal cell division.
"In normal cells, the continued presence of cyclin A prevents the stabilization of microtubules associated with kinetochores, ensuring that cells can correctly correct errors during division."
If the expression of cyclin A is insufficient, microtubule connections will stabilize prematurely, causing cells to be unable to correct errors correctly, which may lead to a high frequency of chromosome misassignment.
In 2001, R. Timothy Hunt, Paul M. Nurse and Leland H. Hartwell jointly won the Nobel Prize in Physiology or Medicine for their discoveries of cyclin and CDK. This is not only recognition of their work, but also opens up a new world for cell cycle research.
This process not only reveals the mystery of the cell cycle, but also integrates the personal interests of scientists into major scientific achievements. This makes us wonder: Can the interests in your life also inspire unexpected innovations?