Creeping and crawling: how cells move

My PhD is in the field of cell biology. More specifically, I am trying to find out how cells ‘feel’ and respond to the environment around them. I am on a one man mission to prove that they are not just boring blobs, but actually fascinating molecular machines!

One process that I work on is cell migration, that is, how cells move around. But why would a cell need to move around? I hear you cry. If you get a cut, your skin cells move together to close up the gap. If you get an infection or mosquito bite, your white blood cells leave the blood stream and migrate to the infected area, causing a red bump to form. Or in the developing foetus, where cells need to move to the correct location.  Cells that are going to become a liver need end up where a liver is meant to be. Problems with this can lead to some terrible diseases, for example, the rare but serious condition where cells that are destined to form the mouth and vocal chords migrate to and end up in the colon, something that I think has happened to Michael Gove.

So, clearly this is an important cellular process, but how does it actually happen. Well don’t migrate away and I’ll tell you. If I want to move from one location to another, I simply walk. But cells don’t have the luxury of legs. However, they do have tiny ‘hands’. These green streaks in the picture below are called focal adhesions. These are points at which lots of different proteins (acting like building blocks) come together and allow the cell to reach outside and hold on to its external surroundings. Through these, it is able to reach forward, grab on, and pull itself forward (using the red ‘rope-like’ fibres in the picture. These are called actin). It then lets go and pushes forward again. So it crawls along.

A cell with focal adhesions (green) and actin filaments (red). These work together to pull the cell along a surface.

A cell with focal adhesions (green) and actin filaments (red). These work together to pull the cell along a surface.

That’s it, that’s how cells move. But just think about that for a second. Each focal adhesion contains potentially thousands of proteins, which need to come together in a precise manner, pull, and then disassemble in a matter of seconds. That’s like doing a 1000 piece jigsaw puzzle in seconds, then pulling it apart and starting again. But there’s more, a cell could have tens or even hundreds of these adhesions, meaning you might have to do 100 1000 piece jigsaw puzzles in seconds, and keep repeating this.

This molecular complexity all contributes to a wonderfully simple process of a cell crawling on a surface, which I think really sums up the beauty of cell biology.

It is this complexity that we need to understand further. The most common and well-known cell migration disease is cancer. If cancer stays put it’s easy. A skilled surgeon can cut it out. Sorted. However, cancer cells are able to migrate much more than normal cells, and it is when the cancer spreads that it really starts to cause problems. So I don’t want to make any bold sweeping statements, but if we can increase our understanding of this process of cell migration, we could probably cure cancer!

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2 Responses to “Creeping and crawling: how cells move”

  1. Stefanie April 29, 2014 at 3:47 pm #

    Question: what happens when you have surgery and say that the cancer is completely removed and in a few years it’s back? And also what is the disease when bone structure grows abnormal, does this also have to do with cell migration and can such diseases be cured ?

  2. Ben Stutchbury January 16, 2015 at 9:08 am #

    Hi Stefanie, firstly sorry I have taken so long to respond. I have had some time away from the blog but have decided to try to start it back up again.

    Firstly, the problem with cancer is that it moves very quickly, it grows very quickly and it can start from just a single cell. When a tumour is removed via surgery, it is entirely possible that one or a few cancer cells are not removed, or they have managed to migrate to another part of the body and there are so few of them that they haven’t yet been detected. Over time, these would grow and form a new tumour. The second possibility is simply that when the cancer comes back in a few years it is an entirely new tumour, with no association to the original. You could only put this down to bad luck!

    Can you be more specific with the second part of your question? I don’t know precisely what disease you mean, but if it is to do with bone growth, for example something like elephantiasis, then this is caused by the bone cells growing too quickly, very similar to cancer. As far as I am aware, this is not a cell migration associated disease.

    Thanks for reading!

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