Scientists track protein linked to movemen...( he cell. For the new study she ...)

For the new study, she engineered defective copies of the torsinA gene and inserted them into cultured mammalian cells. Hanson designed one of the defective genes to make a form of torsinA that would stick permanently to adenosine triphosphate (ATP), a compound cells use to move energy around. Breaking down ATP normally provides torsinA with a great deal of energy, probably enabling it to perform its main job. Hanson hoped making torsinA stick to ATP would trap it at its normal site of action, revealing where in the cell the protein usually works.

The TorsinA that was stuck to ATP moved into the nuclear envelope, the portion of the endoplasmic reticulum that surrounds the nucleus, the central compartment of the cell where DNA is kept.

"Based on what's known about other proteins like torsinA, we figure this means torsinA is probably taking something apart in the nuclear envelope," Hanson says. "The questions are: What is it taking apart and how is that important for the normal structure and function of the nuclear envelope? And how is that activity perturbed by the genetic mutation responsible for DYT1 dystonia?"

Defects in other proteins found in the nuclear envelope recently have been linked to several diseases, including a form of muscular dystrophy and a neuropathy.

"Like any other research, this finding has its caveats," Hanson says. "But we think that there's likely to be some important function that torsinA performs in the nuclear envelope."

Hanson plans further studies to determine torsinA's function.

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Contact: Michael C. Purdy
purdym@wustl.edu
314-286-0122
Washington University School of Medicine
17-May-2004