The research, carried out by a team at Georgetown University in the US, is published in the scientific journal Human Molecular Genetics.
Getting rid of alpha-synuclein
In Parkinson's, sticky bundles of a protein called 'alpha-synuclein' are found inside the brain cells and are believed to play a role in the damage that causes brain cells to die.
Cells have an inbuilt recycling process to get rid of unwanted proteins - but in Parkinson's this doesn't seem to be able to get rid of alpha-synuclein quickly enough.
The system relies on unwanted proteins being 'tagged' for recycling.
In this study, the researchers found that USP-13 - a molecule that removes these recycling tags - is overactive in post-mortem brain tissue from people with Parkinson's.
They were also able to protect against the damaging effects of alpha-synuclein and prevent brain cell death by reducing the activity of USP-13 in experiments in mice.
A route to new treatments
Dr Beckie Port, research communications manager at Parkinson’s UK comments:
"This groundbreaking study highlights a previously unknown reason why the protein may be building up inside the brain cells of people with Parkinson’s.
"Researchers are actively looking for ways to prevent clumps forming as a promising strategy to slow or even stop the progression of Parkinson’s – something no drug is currently able to do.
"Should drugs that target UPS13 stop bundles of the protein forming inside the brains of people with the condition, it could prove to be a real turning point in driving forward the development of treatments that target saving and keeping cells healthy."