Boston, MA (June 19, 2011)Mitochondria, those battery-pack organelles that fuel the energy of almost every living cell, have an insatiable appetite for calcium. Whether in a dish or a living organism, the mitochondria of most organisms eagerly absorb this chemical compound. Because calcium levels link to many essential biological processesnot to mention conditions such as neurological disease and diabetesscientists have been working for half a century to identify the molecular pathway that enables these processes.
After decades of failed effort that relied on classic biochemistry and membrane protein purification, Vamsi Mootha, HMS associate professor of systems biology, and colleagues have discovered, through a combination of digital database mining and laboratory assays, the linchpin protein that drives mitochondria's calcium machinery.
"This channel has been studied extensively using physiology and biophysics, yet its molecular identity has remained elusive," said Mootha, who also has appointments at Massachusetts General Hospital and at Broad Institute. "But thanks to the Human Genome Project, freely downloadable genomic databases, and a few tricks -- we were able to get to the bottom of it."
These findings will appear online June 19 in Nature.
The results build on work from Vamsi and his group over the past decade. In 2008, he and his team published a near-comprehensive protein inventory, or proteome, of human and mouse mitochondria. This inventory, called MitoCarta, consisted of just over 1,000 proteins, most of which had no known function.
In a September 2010 paper, Mootha's group described using the MitoCarta inventory to identify the first protein specifically required for mitochondrial calcium uptake. Their strategy was simple. They knew that mitochondria from humans and Trypanosomes (a parasitical organism), but not baker's yeast, are capable of absorbing large amounts of calcium. By simply overl
|Contact: David Cameron|
Harvard Medical School