ScienceDaily (July 30, 2009) — Italian and U.S. biologists have report that a little-understood protein previously implicated in a rare genetic disorder plays an unexpected and critical role in building and maintaining healthy cells. Even more surprising, their report in the journal Nature shows that the protein, called "atlastin," does its work by fusing intracellular membranes in a previously undocumented way.
"If you'd asked me a year ago whether this was possible, I would have said, 'No,'" said study co-author James McNew, associate professor of biochemistry and cell biology at Rice University. "In fact, that's exactly what I told (co-author) Andrea Daga when we first spoke about the idea a year ago."
Fluorescent markers show the interconnected web of tubes and compartments in the endoplasmic reticulum, the critical part of cells that the protein atlastin helps build and maintain. (Credit: A. Daga/Medea Scientific Institute)
McNew has spent the past 15 years studying SNARE proteins, a specialized family of proteins that carries out membrane fusion. It's a vital process that happens thousands of times a second in every cell of our bodies.
"It is fitting that the discovery of a new protein capable of fusing membranes comes 10 years after the demonstration that SNAREs can fuse lipid bilayers," said Daga, a researcher at the Eugenio Medea Scientific Institute in Conegliano, Italy.
In the new study, Daga's and McNew's research teams used fruit flies to study how atlastin functions. The atlastin in fruit flies is very similar to the human version of the protein and serves the same function.
"Prior to this, there were only two defined ways in which you could take biological membranes and put them together in a specific way," said McNew, a faculty investigator at Rice's BioScience Resesarch Collaborative. "Atlastin is the third, and it's the only one that requires enzymatic activity, so it's distinctly different."
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