A study conducted at the San Francisco VA Medical Center has identified a protein found in both mice and humans that appears to play a key role in protecting neurons from oxidative stress, a toxic process linked to neurodegenerative illnesses including Alzheimer’s and Parkinson’s diseases. The study, led by Raymond Swanson, MD, chief of neurology and rehabilitation services at SFVAMC, identified the protein – known as EAAC1 in mice and as EAAT3 in humans – as the main mechanism through which the amino acid cysteine is transported into neurons. Cysteine is an essential component of glutathione, which Swanson terms “the most important antioxidant in the brain.” It had been thought previously that the main function of the protein was to remove excess glutamate, a neurotransmitter, from brain cells. “It’s known that neurons don’t take up cysteine directly, and it’s never been clear exactly how it gets there,” says Swanson, who is also professor and vice chair of neurology at the University of California, San Francisco. “This study provides the first evidence that EAAC1 is the mechanism by which cysteine gets into neurons – and that transporting cysteine is probably its chief function.” Study findings are currently available in the Advance Online Publication section of Nature Neuroscience.
