What Are Cell Receptors?

Protein Molecules That Change Cell Activity

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Cells, such as the ones in the human body, need a way to interact and communicate with substances such as hormones, drugs, or even sunlight. That's where cellular receptors come in.

A receptor is a protein molecule in a cell or on the surface of a cell to which a substance (such as a hormone, a drug, or an antigen) can bind, causing a change in the activity of that particular cell.​

This article explains how cell receptors work, their role in the human body, and their significance.

receptors on cells
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Function

Here's one way to think of this: a receptor is like a lock, while the substance binding to it is the key to that lock. Thus, only substances keyed to fit the receptor "lock" can bind to a particular receptor.

Substances binding to receptors on cells can tell the cell to:

  • Produce a particular substance: Such as a hormone that makes you feel full after a big meal
  • Divide faster: Maybe causing you to add muscle cells following exercise
  • Die: Chemotherapy drugs binding to cancer cell receptors can signal those cancer cells to self-destruct, for example

Types

Cells' receptors are very specialized, and there are, in fact, hundreds of different types of receptors. Different types respond to different things, such as:

  • Chemical substances such as hormones, drugs, or allergens
  • Pressure
  • Light (your body produces vitamin D, the "sunshine hormone," when sunlight hits your skin)

In some cases, if a cell doesn't have the correct receptor for a particular substance, then that substance won't affect the cell.

For example, leptin is the hormone that causes you to feel full and satiated following a big meal. Cells that don't have receptors for leptin won't respond to that hormone, but those that do will respond, inhibiting the release of other hormones that make you want to eat more.

Significance

Receptors can play both good and bad roles in the human body. In some circumstances, they may contribute to damage caused by certain diseases. In others, they can work with medication to help control certain health conditions.

Celiac Disease

For example, in celiac disease, receptors on specific immune system cells serve as the locks, while fragments of the gluten protein serve as the keys. This interaction triggers celiac's characteristic intestinal damage known as villous atrophy.

Autoimmune Disease

Certain cellular receptors also appear to play a role in causing damage in other autoimmune diseases too. That's because, in an autoimmune disease (like Celiac), your immune system mistakenly turns on and damages some of your body's own cells.

High Blood Pressure

But in some cases, you can use the behavior of cell receptors to support treatment. For instance, in high blood pressure, drugs can fit like keys into the cellular receptors that otherwise would fit a hormone that raises blood pressure.

These drugs are known as angiotensin-blockers because they block the blood pressure-raising hormone angiotensin. As a result, they can help control your blood pressure by preventing angiotensin from signaling cells to raise blood pressure.

Summary

A cell receptor is a protein molecule to which substances like hormones, drugs, and antigens can bind. This allows them to change the activity of a cell.

There are hundreds of types of receptors, all of which respond to different things, such as chemicals, pressure, or light.

Receptors can be responsible for some of the damage that occurs in autoimmune diseases. But, on the other hand, they can also play a role in helping medication bind to a cell to treat some conditions.

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