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Cell proteins are floppy but fast

"For a cell to be viable, molecules must constantly move into and out of its nucleus," said EMBL researcher Edward Lemke.

By Brooks Hays
Fast and flexible proteins can wiggle their way to and from the cell's nucleus without allowing invaders in with them. Photo by Mercadante/HITS
Fast and flexible proteins can wiggle their way to and from the cell's nucleus without allowing invaders in with them. Photo by Mercadante/HITS

HEIDELBERG, Germany, Oct. 9 (UPI) -- Proteins are key to the life of a cell. They travel in and out of cells carrying information to and fro.

Until recently, researchers couldn't figure out how these cellular communicators could move so quickly in and out of cells without compromising security. How do you allow for the flow of messengers without letting in foreign invaders?

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A new study by a team of researchers from Germany, France and Britain is offering answers.

What the scientists found was that flexible and disordered proteins, spaghetti-like in shape, are key to fast-paced inter-cellular communication.

Messenger proteins aren't coming unannounced, they're expected by proteins within the cell walls. Each traveling protein matches up with a subset of receptor proteins -- like a key and lock. And it's the floppy nature of these traveling proteins -- dubbed intrinsically disordered proteins, or IDPs -- that allow them to act as a single but multifaceted key for many locks.

Previously, researchers hypothesized key proteins rearranged themselves to become more rigid and acceptable to the receptor protein, or lock.

Using a combination of high-tech imaging and computer-powered molecular modeling, researchers at the European Molecular Biology Laboratory found the opposite is true.

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"The pioneering single molecule experiments undertaken at EMBL showed for the particular interaction of a receptor with a disordered protein no hint of rigidity: the flexible protein stayed as flexible even when bound to its receptor," researcher Davide Mercadante explained in a press release.

Mercadante and his colleagues published their findings in the journal Cell.

Not all proteins are IDPs, but researchers believe nearly half of all cellular proteins are disordered -- enough to explain the ultra fast (but still secure) communication skills of cells.

"For a cell to be viable, molecules must constantly move into and out of its nucleus," said EMBL researcher Edward Lemke. "Our findings explain the so-called transport paradox -- that is, how this shuttling can be so very fast while remaining specific so that unwanted molecules cannot pass the barrier that protects our genome."

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