So what is it that I do anyway?

I think I have mentioned this before, but I work in fundamental science, which is to say, my research has no direct application. So I try to find the "how this thing happens" so that someone might eventually work on "how can we use this thing that happens".

I work with cells called macrophages, literally big eaters. They get their name because they engulf ("eat") large particles, including other cells, particles and, off course, microbes. We all have them, in different numbers. They make part of what is generally called white blood cells, which includes lymphocytes, neutrophils and other cells. They mainly have a role in the immune response of our body against several diseases.

Now, my project doesn't target a disease in particular. I actually work in an even smaller scale than the cell itself: proteins inside the cell. We are used to hearing mostly about protein in a nutritional context, but what I study it's the role of a single protein in the process that makes the macrophage what it is, an eater.

Now during this process named phagocytosis (a cell eating, basically), there are A LOT of proteins that will regulate the amount of particles that the cell will take in. They will also impact on the fate of the particle, to cut into pieces and telling other cells if the particle is infectious or not, etc. "My" protein is one of those regulators (hey look! It's my first paper!) and that's what my M.Sc work was all about: identifying what, if anything, was the protein doing during phagocytosis and what happened if the protein was no longer there. 

How did I see this you ask? Well, there were mainly two techniques: immunofluorescence and Western Blot. They are both based on antibodies (other type of proteins) recognizing my protein. For the first one, that we will call IF for short, I have my cells and put them in contact with an antibody (Ab) that will "attach" itself to my protein. This Ab can have a tag or I can add it later. Basically, I used a fluorescent tag that will allow me to see where my protein is in the cell once I excite the tag with the right light wavelength.

Here, you can see several cells, the nuclei is marked in blue (with a compound that attaches to DNA) and in green my protein; you can see that the signal is not the same on all cells, and this is normal. This is not one of my best pictures, the blue is a bit saturated, but I just wanted to give you an idea of what it looks like. 

As for the Western Blot (WB), it involves breaking (lysing) my cells with a determined detergent, to extract all the proteins. Then I load this proteins in a gel, and using their weight and their charge, I can separate them using an electric field. After the separation is done, I can transfer the proteins in the gel to a membrane. I will once again put my protein in contact with a specific antibody, this time with an enzyme tag. With the right substrate for the enzyme, the chemical reaction will give a bright signal that I can record using films that are sensitive to light.

Here, on top, you see the signal I got on my film, whereas on the bottom, you can see an example of the gel that I colored with a compound that will mark ALL proteins. As you can see, there is a lot more proteins in my samples, but since I am interested in one in particular, I have to use something specific, hence the antibody.
During my PhD, the research topic changed to WHO was working along with the protein. You may or may not know this, but proteins like to work together. And so my quest to find my protein's partners in crime started and, boy has it been a big quest. Protein interactions can be very hard to study because while they can be highly specific, they are also very delicate. Working at the wrong temperature can change everything,

That is on a VERY big picture what I do but it should give you an idea of what my research is based on. Please let me know if you would like more details or a better explanation on anything I mentioned. Have a wonderful week and in the mean time, keep doing good science. 

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