The Mansfeld Lab
Cell Cycle
To divide, or not to divide? That is the question.
​Our bodies are made of trillions of cells. But in the beginning, there was only one. It divided to give rise to two cells, which later became four and so on. To divide, each cell goes through a strict order of events called the cell cycle. These events include duplicating everything within the cell, so that there will be enough to eventually make two cells, and then checking that everything has been duplicated correctly before division.
But division is not the only fate for cells – they can also decide to stop dividing and become dormant. In fact, an adult human body consists mostly of dormant cells. There is still a lot for us to understand about how cells make decisions throughout the cell cycle, such as this decision between dividing or becoming dormant.
Our laboratory aims to discover more about how cells make these decisions, and what happens when this decision-making goes wrong; for example, uncontrolled cell division which can cause cancer.
Protein Modifications
Most jobs that happen in our cells – essential processes that keep us alive – are carried out by large molecules called proteins. For example, proteins are needed for various jobs during the cell cycle; these are called cell cycle proteins.
Certain molecules can be temporarily added to a given protein, thus ‘modifying’ the protein. This can change its activity, like what type of job it carries out, or when.
Our lab investigates how specific protein modifications affect the activity of cell cycle proteins, especially modifications that are common in cancer.
Reactive Oxygen
One type of molecule that can modify proteins is reactive oxygen species (ROS). As the name suggests, ROS are extremely reactive and can damage lots of delicate structures within cells. An example of ROS is hydrogen peroxide, the chemical we use to bleach hair and clean bathrooms. ROS are produced by many processes that happen continuously in cells – including the processes that keep us alive!
So, if cells can’t avoid producing ROS, then how do they deal with this problem? They produce antioxidants (which can also be found in health foods, like blueberries and dark chocolate) to soak up the harmful ROS molecules.
But there’s a twist in the story: in small amounts, ROS may be needed by the cell, to modify proteins and therefore change their activities. Protein modification by ROS is not widely studied, so our lab is investigating the importance of these modifications, especially for processes that are linked to cancer, such as the cell cycle. We have already found some proteins that need to be modified by ROS to complete the cell cycle correctly!