At this moment, more than one million Americans are living with Parkinson’s disease, a progressive disorder of the nervous system that leads to severe speech, movement, and coordination impairment. People with Parkinson’s suffer from tremors, painfully rigid muscles, and a decreased ability to perform involuntary movements such as blinking, smiling, and gesturing while talking.
There is currently no cure for this disease nor is there a known cause, although genetics and environmental factors have been shown to play a role. A few days ago, however, researchers at McGillUniversity located in Montreal, Quebec, Canada discovered the three-dimensional structure of the protein Parkin, a protein responsible for protecting neurons from cell death by preventing defective mitochondria from building up. Mutations in Parkin cause rare heredity forms of Parkinson’s and are likely involved in other more commonly occurring forms of the disease as mitochondria-damaging toxins are known to cause Parkinson’s-like symptoms in humans and animals. Parkin is an enzyme in cells that attaches a small protein, ubiquitin, to other proteins to mark them for destruction. For example, when mitochondria are damaged, Parkin is “switched on” which results in the clearing of the defective mitochondria. This is important because damaged mitochondria play a major role in the death of neurons in diseases such as Parkinson’s.
The recent knowledge of Parkin’s structure has allowed scientists to create mutations in Parkin that make it better at recognizing damaged mitochondria. This would better protect neurons and prevent them from losing function or dying. Dr. Gehring, head of McGill`s structural biology center, calls Parkin a “watchdog” for damaged mitochondria. “Our structural studies show that Parkin is normally kept in check by a part of the protein that acts as a leash to restrict Parkin activity. When we made mutations in this specific ‘leash’ region in the protein, we found that Parkin recognized damaged mitochondria more quickly,” Gehrig said. With this new research, scientists may be able to reproduce this response with a drug, slowing the progression of this devastating disease.