Using The Force: Cell Signals
My name is Ben Stutchbury and I am a second year cell biology PhD student, looking at how cells sense and respond to the environment around them. I did my undergraduate degree in molecular biology, which I also did at the University of Manchester.
For a long time, the way that cells sense and respond to the environment around them was thought to be only due to chemical signals. Cells produce different chemicals and proteins that attach to other cells, transmitting a message and triggering a response, just like sending and receiving a text message. However, recently it has been seen that cells are also able to sense and respond to mechanical signals, rather than just chemical signals. I am trying to figure out how cells are able to do this, and the important role that these mechanical signals play in the cell.
The mechanical properties of different tissue types vary all over the body. Brain is extremely soft, muscle a bit stiffer and bone the most rigid. Studies have shown that these different mechanical properties can affect several different aspects of cell behaviour such as how fast they grow, how quickly they move or even affect what type of cell they become.Now imagine you are a cell, how do you know where you are? Cells don’t have a sense of sight, smell or hearing, but… they do have an extremely sensitive sense of touch.
Hundreds of proteins come together in a defined and intricate order to form streak-like structures known as focal adhesions (shown in green in the picture). These form at the edge of the cell, and reach outside, literally grabbing onto the surrounding environment. Basically acting like a cell’s tiny hands. Using these hands, the cell then blindly pulls and probes on the external environment, feeling its mechanical properties and the forces acting on the cell. Now, as I said before, as well as feeling their environment, cells will also respond it. If the environment around it changes, for example becomes softer or stiffer, then the forces acting on the cell will change. The cell, via its focal adhesion hands, is able to feel and respond to these changes. They are quite literally using the force! This signalling is extremely important for the cell to function correctly and can go wrong in a number of diseases such as cancer and heart disease.
So we know that cells are responding to physical changes to their environment. But, we don’t know exactly how the cell is able to feel these mechanical signals and convert them into a response. My work is to try to determine the exact molecular events that are involved in sensing, and responding to, these mechanical signals. I am trying to work out HOW the cells use the force. This could lead to a better understanding, and treatment of, a number of associated diseases.
I particularly enjoy studying this topic because it is a very ‘new’ area of biology. For years biologists focussed on the chemical side of cell signalling; however, now we are just beginning to see the importance of this more physical-based signal interpretation. This means there is still a lot to be discovered, which makes it a very exciting field to work in. We work a lot with various biomaterials, in order to manipulate the ‘stiffness’ of the artificial environment that the cells are growing in. This uses aspects of physics and engineering and really highlights the importance of cross-collaboration between these different areas in order to fully understand the complexity of our bodies.
I also write a blog about science that we come across in our everyday lives, but is often ignored. Please check it out here: http://thatsinteresting.scienceblog.com/
As I mentioned, this is a relatively young field, so there aren’t a huge number of websites with further information that aren’t boring research papers! Here are some that I could find.
Our lab group: http://ballestremlab.com/
For general info about cell signalling: http://www.nature.com/scitable/topicpage/cell-signaling-14047077
The mechanobiology institute in Singapore has some pretty cool videos on their YouTube channel. https://www.youtube.com/channel/UCDXgKXsx2cK-662Ta6wvtEQ