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Clue to Mechanism by Which Certain Gene Mutations Cause Familial Parkinson’s
Researchers at the Mount Sinai School of Medicine and collaborating institutions have discovered a way that mutations in a gene called LRRK2 may cause the most common inherited form of Parkinson's disease. The study, published online on March 1, 2011, in the journal PLoS ONE, shows that upon specific modification called phosphorylation, LRRK2 protein binds to a family of proteins called 14-3-3, which has a regulatory function inside cells. When there is a mutation in LRRK2, 14-3-3 is impaired, leading to Parkinson's. This finding explains how mutations lead to the development of Parkinson's, providing a new diagnostic and drug target for the disease. Using one-of-a-kind mouse models developed at the Mount Sinai School of Medicine, Dr. Zhenyu Yue, Associate Professor of Neurology and Neuroscience, and his colleagues, found that several common Parkinson's disease mutations—including one called G2019S—disturb the specific phosphorylation of LRRK2. This impairs 14-3-3 binding to varying degrees, depending on the type of mutation. "We knew that the LRRK2 mutation triggers a cellular response resulting in Parkinson's disease, but we did not know what processes the mutation disrupted," said Dr. Yue. "Now that we know that phosphorylation is disturbed, causing 14-3-3 binding to be impaired, we have a new idea for diagnostic analysis and a new target for drug development." Dr. Yue's team also identified a potential enzyme called protein kinase A (PKA), responsible for the phosphorylation of LRRK2. Although the exact cellular functions disrupted by these changes are unclear, the study provides a starting point for understanding brain signaling that contributes to the disease.