The cystic fibrosis transmembrane conductance regulator (
To understand how mutations in the
What Are Proteins?
Proteins are tiny machines that do specific jobs within a cell. The instructions for building each protein are encoded in
What Does the
CFTR Protein Do?
The CFTR protein is a particular type of protein called an
Once the chloride ions are outside the cell, they attract a layer of water. This water layer is important because it allows tiny hairs on the surface of the lung cells, called cilia, to sweep back and forth. This sweeping motion moves mucus up and out of the
How Do Problems With the CFTR Protein Cause CF?
In people with CF, mutations in the CFTR gene can cause the following problems with the CFTR protein:
- It doesn't work well
- It isn't produced in sufficient quantities
- It is not produced at all
When any of these problems occur, the chloride ions are trapped inside the cell, and water is no longer attracted to the space outside the cell. When there is less water outside the cells, the mucus in the airways becomes dehydrated and thickens, causing it to flatten the cilia. The cilia can't sweep properly when thick, sticky mucus weighs them down.
Because the cilia can't move properly, mucus gets stuck in the airways, making it difficult to breathe. In addition, germs caught in the mucus are no longer expelled from the airway, allowing them to multiply and cause infections. Thick mucus in the lungs and frequent airway infections are some of the most common problems people with CF face.
Researchers Are Still Studying the Basic Structure
Researchers are still trying to learn more about the structure of the CFTR protein so that they can find new and better ways to help improve the function of the protein in people with CF.
Because the 3-D shape of CFTR is so complex, it was not until early 2017 that the first high-resolution pictures were developed. These pictures have given researchers important clues about where drugs bind the protein, how they affect its function, and how to develop new CF therapies. In the future, pictures showing the protein in an “open” position, where salt can move through, will be even more helpful to researchers developing new CF therapies.