Researchers have identified a protein that acts as a powerful protectant against free radicals -- a molecule that causes cell damage and death as well as ageing.The findings showed that Lysosomes -- the protein that comprise the cell's recycling centre, are crucial for cleaning up injured and dying parts of the cells.“Free radicals are guilty in the ageing process. If we have chemical compounds that can directly activate this channel, we can lower the oxidative stress in ageing and other diseases," said lead researcher Haoxing Xu, Associate Professor at University of Michigan, in the US.Lysosomes were found to have a radical-sensing ability to know that the body has many free radicals.Thus, when lysosomes "sense" an overload of free radicals, they activate a calcium channel on their membranes.This triggers the expression of many genes and the production of more and stronger lysosomes, which spurs into overdrive to get rid of the damaged parts of the cells."The result will be that cell damage and free radical levels could be reduced, and one can possibly slow down ageing," Xu added.Ironically, the protein is activated by excessive free radicals. Human mutations of the gene for this protein are previously known to cause a rare, neurodegenerative disease, said the paper published in the journal Nature Communications.