What type of transport is cftr

People with CF has very salty sweat. The sweat gland secretes salt and water some of which is typically reabsorbed in the sweat duct. This reabsorption process is markedly abnormal in people with CF.

Chloride transport is virtually eliminated because CFTR located on the surface of the cells in the sweat duct is defective. The high chloride concentration in the sweat can be used to diagnose people with CF.

The airways are covered with a thin, layer of liquid called airway surface liquid ASL and a mucus gel layer. The mucus layer traps bacteria and foreign particles, while cilia on the surface of airway cells constantly move the particles out of the lungs and toward the mouth. This process, called mucociliary clearance is an important defense mechanism that protects the lungs from infection. The ASL also contains antiproteases, antioxidants, antibodies and other substances that work together to neutralize or destroy invading organisms without damaging the lungs.

In CF airways, decreased chloride transport is coupled with excess sodium reabsorption out of the ASL. Since water follows the flow of sodium the ASL and the mucus gel layer become dehydrated. The exocrine pancreas produces enzymes that digest food. Most people with CF do not make pancreatic enzymes leading to a problem called pancreatic insufficiency.

The pancreatic duct cells also secrete bicarbonate into the intestine to neutralize stomach acid via the CFTR channel. The inability to neutralize stomach acid contributes to malabsorption in many people with CF. Coding, construction and placement of the CFTR protein. Construction and placement of the CFTR protein in the cell membrane occurs in distinct phases. Located on the long q arm of chromosome 7 at position These mutations allow the CFTR protein to retain some of its function.

Some affected males have a mild mutation in one copy of the CFTR gene in each cell and a more severe, cystic fibrosis-causing mutation in the other copy of the gene. Mutations in the CFTR gene disrupt the function of the chloride channel, preventing the usual flow of chloride ions and water into and out of cells. As a result, cells in the male genital tract produce mucus that is abnormally thick and sticky.

This mucus clogs the tubes that carry sperm from the testes the vas deferens as they are forming, causing them to deteriorate before birth. Without the vas deferens, sperm cannot be transported from the testes to become part of semen.

Men with congenital bilateral absence of the vas deferens are unable to father children infertile unless they use assisted reproductive technologies. More than 1, mutations in the CFTR gene have been identified in people with cystic fibrosis. The most common mutation, called delta F, is a deletion of one amino acid at position in the CFTR protein. The resulting abnormal channel breaks down shortly after it is made, so it never reaches the cell membrane to transport chloride ions.

Disease-causing mutations in the CFTR gene alter the production, structure, or stability of the chloride channel. All of these changes prevent the channel from functioning properly, which impairs the transport of chloride ions and the movement of water into and out of cells. As a result, cells that line the passageways of the lungs, pancreas, and other organs produce mucus that is abnormally thick and sticky. The abnormal mucus obstructs the airways and glands, leading to the characteristic signs and symptoms of cystic fibrosis.

A few mutations in the CFTR gene have been identified in people with isolated problems affecting the digestive or respiratory system. For example, CFTR mutations have been found in some cases of idiopathic pancreatitis, an inflammation of the pancreas that causes abdominal pain, nausea, vomiting, and fever. Although CFTR mutations may be a risk factor, the cause of idiopathic pancreatitis is unknown. Changes in the CFTR gene also have been associated with rhinosinusitis, which is a chronic inflammation of the tissues that line the sinuses.

This condition causes sinus pain and pressure, headache, fever, and nasal congestion or drainage. Other respiratory problems, including several conditions that partially block the airways and interfere with breathing, are also associated with CFTR mutations. These conditions include bronchiectasis, which damages the passages leading from the windpipe to the lungs the bronchi , and allergic bronchopulmonary aspergillosis, which results from hypersensitivity to a certain type of fungal infection.

Cystic fibrosis occurs when the cystic fibrosis transmembrane conductance regulator CFTR protein is either not made correctly, or not made at all. By understanding how the protein is made, scientists have been able to develop treatments that target the protein and restore its function. The cystic fibrosis transmembrane conductance regulator CFTR protein helps to maintain the balance of salt and water on many surfaces in the body, such as the surface of the lung. When the protein is not working correctly, chloride -- a component of salt -- becomes trapped in cells.

Without the proper movement of chloride, water cannot hydrate the cellular surface. This leads the mucus covering the cells to become thick and sticky, causing many of the symptoms associated with cystic fibrosis. To understand how mutations in the CFTR gene cause the protein to become dysfunctional, it is important to understand how the protein is normally made, and how it helps to move water and chloride to the cell surface.

Proteins are tiny machines that do specific jobs within a cell. The instructions for building each protein are encoded in DNA. Proteins are assembled from building blocks called amino acids. There are 20 different amino acids. All proteins are made up of chains of these amino acids connected together in different orders, like different words that are written using the same 26 letters of the alphabet.

The DNA instructions tell the cell which amino acid to use at each position in the chain to make a specific protein. The CFTR protein is made up of 1, amino acids.