Scientists at La Trobe University have created a world-first method to investigate 'disordered' proteins in living cells, in breakthrough research that could revolutionise how we understand and treat Parkinson's disease.
Pictured: Dr Tze Cin Owyong, Associate Professor Yuning Hong, Dr Shouxiang Zhang
Published in Nature Methods, the research used a cutting-edge chemical tag called TME, which binds with the proteins and makes them light up, allowing scientists for the first time to detect and capture them for analysis while in their unstructured or 'disordered' state.
The research also showed that using TME with existing investigative methods offers critical new insights into Parkinson's disease by revealing how the proteins behave in living blood cells - a breakthrough which could help scientists better understand the causes of the disease.
Lead researcher Associate Professor Yuning Hong said the new chemical tool marked a significant advance in biological and biomedical research, and a crucial step towards the development of better treatments and eventually a cure for Parkinson's disease.
"In nearly 85 per cent of cases of Parkinson's disease the causes are unknown, but we do know that abnormal clumps or 'aggregates' of these proteins are a marker of the disease in its advanced stages," Associate Professor Hong said.
"Not much is known about these proteins as previously they couldn't be identified in live cells using traditional methods. With our TME chemical tag, researchers can now analyse the proteins' behaviour directly in living cells - critical information for Parkinson's disease and other neurodegenerative diseases."
Disordered proteins differ from other protein types as they are not neatly folded to have a three-dimensional structure, giving them a unique flexibility which is key to their function and how they interact with other molecules.
However, abnormal behaviour in these proteins can lead to neurodegenerative disorders, including Parkinson's disease, dementia and Huntington's disease.
La Trobe University researcher Dr Shouxiang Zhang, the paper's first author, said current methods to analyse disordered proteins' behaviour required scientists to first kill the cells they were housed in - a process which could change the proteins' natural state.
"Disordered proteins are highly dynamic and heterogenous - their structure changes shape depending on their environment and killing the cell could alter their behaviour," Dr Zhang said.
By using TME to chemically tag disordered proteins, scientists can for the first time track their behaviour directly inside living cells.
When used in combination with other existing workflows, the tag helps scientists capture and concentrate the proteins for analysis on a large scale, giving crucial insight into how they change over time under different conditions.
For this study, the research team used TME to identify disordered proteins in Parkinson's disease and Huntington's disease.
They found it was better than traditional methods in differentiating the blood cells of Parkinson's disease patients from healthy individuals. For Huntington's disease, it revealed the mechanism of how affected cells trap disordered proteins in clusters.
Associate Professor Hong said understanding this mechanism was crucial information which opened new avenues of research to investigate the causes not only of Huntington's, but also Parkinson's.
"What leads to the proteins forming aggregates in the first place? Is it protective or is it detrimental to the cells? Using TME, we hope that researchers can answer these questions and design new treatments based on what they learn by observing the proteins' behaviour in live cells over time," Associate Professor Hong said.
In the future, Associate Professor Hong hopes to create similar tests to help scientists investigate other diseases.
"More than 50 human diseases have been linked to abnormal protein behaviour and disordered proteins, including Alzheimer's disease, cystic fibrosis, type 2 diabetes, and certain cancers," Associate Professor Hong said.
"It was clear that there was a need in disease research for the kind of test we have developed and we hope in the future it can help scientists uncover more about the role of disordered proteins in a wide range of diseases."
Associate Professor Hong is a member of the La Trobe Institute for Molecular Science (LIMS), and La Trobe's School of Agriculture, Biomedicine and Environment (SABE).
This study was conducted as a part of Associate Professor Hong's Australian Research Council (ARC) Future Fellowship and National Health and Medical Research Council (NHMRC) Ideas grant and was initially funded by the Rebecca L. Cooper Medical Research Foundation Project Grant.
It was done in collaboration with scientists at the University of Melbourne, the Research Centre for Molecular Medicine (CeMM) of the Austrian Academy of Sciences and the Northwestern University in the United States.
Read the paper, "Global Analysis of Endogenous Protein Disorder in Cells" in Nature Methods here.
