Proteins in the Cell

In every cell in your body, proteins are constantly being produced. In fact, the majority of the cell is devoted to the creating and altering proteins for one role or another. (You can learn how the cell produces proteins in the Genes and Proteins section.) While you may have heard of protein in your food as something you need to eat, the word protein in biology means something a little different. And, since the cell spends so much time making proteins, the obvious question is what these proteins actually do in the cell. Thankfully, this question has a simple answer. Proteins do everything. If we pretend that your body is a house then proteins are the walls, floor, ceiling, wiring, plumbing, furniture, builders, repairmen, and residents.
To give a few examples, consider the following proteins:

Fibrillin: Structural protein, responsible for cell microfilaments. Structural proteins like Fibrillin are responsible for making the shape of the cell and holding its parts together, as well as moving the cell around.

Myoglobin: Transport protein in blood cells, carries oxygen. Transport/Signaling proteins like Myoglobin are responsible for carrying chemicals where they are needed within and between cells.

Hexokinase: Enzyme protein, catalyzes reactions. Enzymes like Hexokinase are responsible for allowing the reactions that occur within cells when they would otherwise be too slow to keep the cell alive.

Note:These images are false color images designed to show different parts of the protein, but the shapes are found from actual proteins.

These color models represent three entirely different proteins, and while they look like strange twisted masses, they are actually carefully folded and tailored to their purpose. These are just a few examples, but offer a stunning example of the wide array of roles that proteins can fulfill in the cell.

Proteins are so common that regardless of what you are researching, from diseased cells like cancer to normal cell processes like mitosis, you are most likely focusing on one or more proteins. The obvious downside is that because proteins are so common, it is incredibly hard to isolate any single protein in the cell and figure out what it does, which is essential to the production of medicine or the understanding of a disease or cell process. To this day, there are a large number of proteins whose role in the cell is not understood, and likely an even larger number of proteins that have never been discovered at all. Because of the difficulty in isolating and studying proteins once they have formed, scientists have developed a number of tricks. One of the most potent is using siRNA, as the Whitehurst lab did, to disrupt and remove a single protein from a cell. You can learn more about siRNA in the Gene Manipulation section.