Scientists have taken what they say is a “vital step” towards understanding the origins of Parkinson’s disease.

A new study details findings about what a key protein called alpha-synuclein actually does in neurons in the brain.

Researchers say that in order to cure the disease, it is necessary to understand the function of this protein.

When the protein functions normally, it plays an important part in the mechanisms by which neurons exchange signals in the brain.

But it can malfunction and begin to stick together in clumps which eventually spread and kill healthy brain cells.

Dr Giuliana Fusco, research fellow at St John’s College, University of Cambridge, and lead author of the paper, said: “This study could unlock more information about this debilitating neurodegenerative disorder that can leave people unable to walk and talk.

“If we want to cure Parkinson’s, first we need to understand the function of alpha-synuclein, a protein present in everyone’s brains.

“This research is a vital step towards that goal.”

Parkinson’s is a progressive neurological disorder that causes nerve cells in the brain to weaken or die.

The disease has a variety of symptoms including tremors – particularly in the hands – gait and balance problems, slowness and extreme stiffness in the arms and legs.

It develops when cells in the brain stop working properly and cannot produce enough dopamine – a chemical that controls movement in the body by acting as a messenger between cells.

The disease mostly affects those over the age of 60 and gets progressively worse but early onset Parkinson’s can affect younger people.

More than 10 million people worldwide live with Parkinson’s, including actor Michael J Fox, who was diagnosed at 29, singer Neil Diamond, comedian Sir Billy Connolly and musician Ozzy Osbourne.

While the disease can affect women, men are more likely to have Parkinson’s.

It is not yet known why people get the disease, but researchers think a combination of age, genetic and environmental factors cause the dopamine-producing nerve cells to die, affecting the body’s ability to move.

The new study, published in the journal Nature Communications, looked at what was going on inside healthy conditions to help pinpoint what is going wrong in the cells of people with Parkinson’s.

All cells in the body have a plasma membrane that protects cells and usually transports nutrients in, and clears toxic substances out.

Dr Fusco said: “One of the top questions in Parkinson’s research is, what is the function of alpha-synuclein, the protein that under pathological conditions forms clumps that affect motor and cognitive abilities?

“Usually you discover a protein for its function and then you explore what is going wrong when disease strikes; in the case of alpha-synuclein, the protein was identified for its pathological association but we didn’t know what it did in the neuron.

“Our research suggests that the alpha-synuclein protein sticks like glue to the inner face of the plasma membrane of nerve cells but not to the outer – a crucial new piece of information.”

The scientists used synthetic models to mimic brain cell membranes during the study.

There are treatments and drugs available to Parkinson’s patients and the disease is not fatal, but nothing is available to reverse its effects.

Introducing lifestyle changes including getting more rest and exercise can alleviate symptoms.

Scientists say more research is needed before drug therapies can be developed to tackle the origins of Parkinson’s disease.