How do the power plants of the cell—the mitochondria—use their defence mechanisms to fight diseases such as Parkinson’s disease? This debilitating disorder is caused by an accumulation of proteins that have folded incorrectly.

The misfolded proteins then clump together and form sticky, cell-damaging deposits called plaques.

“We know that mitochondria are at the centre of the aging process,” says Prof Nick Hoogenraad, executive director of the La Trobe Institute for Molecular Science (LIMS). Nick and his team have found a mechanism mitochondria use to remove the plaques that are prone to form as we age.

While cells possess mechanisms to prevent misfolded proteins, the mitochondria—which are composed of membranes and genetic material similar to a miniature cell—have their own defences to remove unfolded proteins, including enzymes called proteases and chaperones, which break down proteins.

“Mitochondria import most of the compounds used to protect them from misfolded proteins from elsewhere in the cell,” Nick says. “So far, we’ve worked out the signalling pathway that tells the cell nucleus to produce the right protective proteins, but we don’t know how the mitochondria senses misfolding or how it starts the signalling process.”

Nick, a global authority on mitochondria, has the goal of finding a way to stimulate the cell to make higher levels of these protective proteins. “We’re trying to find a drug that increases the level of proteases. This would mean greater protection against the misfolded proteins that cause Parkinson’s disease.”

Nick and his colleagues will continue their work in the $94.1 million La Trobe Institute for Molecular Science (LIMS) when it opens in 2013.

Photo: The body’s power plant mitochondria.
Credit: Istockphoto.

La Trobe Institute for Molecular Science (LIMS), Nick Hoogenraad, N.Hoogenraad@latrobe.edu.au, www.latrobe.edu.au/lims/about