What is a Receptor?
Art & Research: Kadir Özler
Further Reading Literature: Kadir Özler
Reviewed by Expert: Robert Lucito, PhD
The Receptor
What is a receptor and what does it do?
Receptors are proteins that cells have on their surface or within that are used to "bind" (or attach) to signals from the environment so that the cell can respond. Receptors are very important for communication between cells.
These signals from the environment are called ligands, and these ligands are the targets that receptors bind in order to allow a response from the cell.
This is like one cell high-fiving another cell to send a signal to that target cell, only a little more complex.
Note that this form of direct signaling between cells is not the most common form, but it is used here to simplify the process of information transmission between cells.
Receptor + Ligand
The interaction between these cells in reality is more of a fist-in-hand interaction. The open hand is found on the target cell (the one receiving the new information and serves as the receptor. The closed fist that will fit into the open hand is the ligand - it may be a direct connection from another cell or a protein released from a distant cell that binds to the receptor.
Receptors are very complex proteins with grooves and folds, so when a ligand that fits these grooves and folds very well into the receptor comes along, the cell can recognize this target protein because of this correct fit. Think of this as a first that correctly fits the shape of the open hand.
Diversity of Receptors
All cells within the body have receptors, but not every cell has the same receptors present.
This makes sense since the cells in the eye serve different functions than cells in the intestine.
For example, vision-related ocular nerves can release ligands that bind to receptors on other neurons that eventually carry the information from what we see to the brain. In the gut, the contents of our food, like sugars, can act as ligands and bind to receptors on our intestinal cells. This allows the gut to recognize the food particles and then absorb them for digestion.
Cell Signaling
In summary, there a trillions of cells within our body, many of which receive information from other cells through their receptor-ligand interactions.
There may be proteins released from distant locations like the brain that act on the receiving cell. There can be direct connections between the receiving cell and a ligand on the surface of a nearby cell. Additionally, the cell itself can often release proteins into the environment that can interact with that very same cell!
Thus, these receptor-ligand signaling events are everywhere and are important for balance of biological processes necessary for life. These signals can even be modified for cancer treatments, pain therapy, and much more!