Peptide discovered in scorpion venom may hold key to secretor...( Researchers have discovered a peptid...),Health

Researchers have discovered a peptide in scorpion venom that may hold the key to understanding and controlling cystic fibrosis and other secretory diseases.

In the December 28 issue of the Journal of Biological Chemistry, an international team of researchers describes how this novel peptide, called GaTx1, can control the movement of ions and water out of cells by interacting with a crucial chloride channel. This research was funded by the National Institutes of Health, National Science Foundation and Cystic Fibrosis Foundation.

Peptide toxins from scorpions, snakes, snails and spiders paralyze prey by blocking nerve or muscle ion channels so the prey cant get away, explained Nael A. McCarty, an associate professor in the Georgia Institute of Technologys School of Biology. Those toxins have been enormously useful for studying the potassium, calcium, and sodium channels that they interact with, but this is the first toxin discovered that potently binds to and selectively and reversibly inhibits a chloride channel of known molecular identity.

Chloride channels are crucial for secretion in many epithelial tissues, but little has been known about their structures and mechanisms. Researchers do know that chloride channels open to allow millions of chloride ions to travel through them and out of epithelial cells. This movement creates an osmotic gradient that allows water to flow.

For the more than 70,000 people worldwide affected by cystic fibrosis, a lack of water flow in airway cells results in abnormally thick, sticky mucus that commonly causes blockages that obstruct airways and glands. The lack of water flow stems from a problem in a chloride channel called the cystic fibrosis transmembrane conductance regulator (CFTR) protein.

In individuals with cystic fibrosis, the CFTR protein is mutated, often with one or more amino acids deleted, and consequently misfolded. In the most common CFTR
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