The study, published in the February 6, 2003, issue of the journal Nature, and led by Howard Hughes Medical Institute investigators at Duke University Medical Center, found that a rare fatal heart condition, called long QT syndrome (LQTS), can be caused by disruption of proteins that anchor ion channels in the cell.
The finding is noteworthy because most cases of LQTS, and some other known heart conditions, have involved defects in ion channels -- proteins involved in moving potassium and other ions in and out of heart cells so they can contract. In this case, however, the channels and the molecular transporters function normally, but the proteins that position and anchor the channels on the heart cells are awry.
"It's as if the lights on your car work fine, but they are being held in the wrong positions, such as on the sides of the car, so that you can't use them to drive at night," said HHMI investigator and Duke cell biologist Vann Bennett, senior member of the research team. "Here, membrane channels work properly, but they are poorly organized on the cell, and that affects a critical biological process in which multiple ion channels need to open at the right place and at the right time."
Of even more interest to researchers is the fact that the protein, ankyrin-B, is found in cells throughout the body, raising the possibility that malfunctions in this protein or in other members of the ankyrin family of molecules, may be the root of other disorders. "We have shown for the first time that a protein that most of us thought was just one of many cellular housekeepers actually has an important role in organizing ion channels," Bennett said. "And if it doesn't work right, you can hav
Contact: Jim Keeley
Howard Hughes Medical Institute