Researchers at Johns Hopkins' Institute for Cell Engineering (ICE) have discovered a protein that could be the best new target in the fight against Parkinson's disease since the brain-damaging condition was first tied to loss of the brain chemical dopamine.
Over the past year, the gene for this protein, called LRRK2 (pronounced "lark-2"), had emerged as perhaps the most common genetic cause of both familial and unpredictable cases of Parkinson's disease. Until now, however, no one knew for sure what the LRRK2 protein did in brain cells or whether interfering with it would be possible.
Now, after studying the protein in the lab, Johns Hopkins researchers report that the huge LRRK2 protein is part of a class of proteins called kinases and, like other members of the family, helps control other proteins' activities by transferring small groups called phosphates onto them. The researchers also report that two of the known Parkinson's-linked mutations in the LRRK2 gene increase the protein's phosphate-adding activity. The findings appear in the current (Nov. 15) issue of the Proceedings of the National Academy of Sciences.
"We know that small molecules can interfere with this kind of activity, so LRRK2 is an obvious target for drug development," says Ted Dawson, M.D., Ph.D., co-director of the Neural Regeneration and Repair Program within ICE and a leader of the study. "This discovery is going to have a major impact on the field. It's going to get people talking about kinase activity."
Because kinases affect a number of other proteins, LRRK2's link to Parkinson's may be a result of either its own activity or a shift in the activities of one or more "downstream" proteins.
"The next step is to prove that LRRK2 overactivity results in the death of brain cells that produce dopamine, the defining pathology of Parkinson's disease, and to figure out how it does so," says Dawson, who cautions that the large size of the LRRK2 gene
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Contact: Joanna Downer
jdowner1@jhmi.edu
410-9614-5105
Johns Hopkins Medical Institutions
18-Nov-2005