Membrane proteins: Communicating with the world across the border

May 15, 2014

All living cells are held together by membranes, which provide a barrier to the transport of nutrients. They are also the communication platform connecting the outside world to the cell's interior control centers. Thousands of proteins reside in these cell membranes and control the flow of select chemicals, which move across the barrier and mediate the flux of nutrients and information. Almost all of these pathways work by protein handshakes—one protein "talking" to another in order to, for example, encourage the import of a needed nutrient, to block a compound from accumulating to a toxic level, or to alert the cell's interior to changes in the outside environment.

Little was known about the relationships among and interior proteins. A team led by Carnegie's Wolf Frommer has revealed how membrane proteins were networked with each other and with the inside the cell. Their work is published in Science.

The messages conveyed to membrane proteins by signaling proteins, and vice versa, form the basis of communication between cells within an organism, as well as between the organism and the outside world. To gain insight into this protein-protein messaging across and within membranes, the Frommer team carried out a massive screen for protein-protein interactions between predicted membrane proteins and predicted signaling proteins. They focused on a mustard green called Arabidopsis, the reference organism used by plant biologists in their research.

Many millions of tests were performed and over 10,000 interactions were discovered. The work is the first of its kind in any organism and will have implications for both plant and animal sciences.

Technical difficulties in studying membranes mean that only a few cross-membrane protein-to-protein signals are known. Both plant and human genomes contain thousands of membrane proteins whose functions remain mysterious. Similar techniques to identify membrane protein interactions have been used before to identify select membrane transporters. But Frommer's team developed a deeper process that was able to yield a greater diversity of results. The vast majority of the thousands of potential membrane protein-signaling protein interactions they found had never before been identified. The team's aim was to use their new protein interaction network to identify interactions important for protein-protein messaging and help assign possible functions to these "unknown" membrane proteins.

"Our findings can serve as an important resource for gene discovery and will be applicable to the animal kingdom, as well as to plants," Frommer said. "In plants, it could help lead to discoveries that will improve crop yields."

Explore further: Researchers discover new mechanism of DNA repair

More information: "Border Control—A Membrane-Linked Interactome of Arabidopsis" Science, 2014.

Related Stories

Plants recycle too

Feb 13, 2014

A research team from VIB and Ghent University (Belgium), and Staffan Persson from the Max Planck Institute of Molecular Plant Physiology in Potsdam (Germany) has now identified a new protein complex which is crucial for endocytosis ...

Molecular biology mystery unravelled

Feb 18, 2014

The nature of the machinery responsible for the entry of proteins into cell membranes has been unravelled by scientists, who hope the breakthrough could ultimately be exploited for the design of new anti-bacterial ...

Protein structure: Peering into the transit pore

Feb 07, 2014

The lipid-rich membranes of cells are largely impermeable to proteins, but evolution has provided a way through – in the form of transmembrane tunnels. A new study shows in unmatched detail what happens ...

Recommended for you

Researchers discover new mechanism of DNA repair

5 hours ago

The DNA molecule is chemically unstable giving rise to DNA lesions of different nature. That is why DNA damage detection, signaling and repair, collectively known as the DNA damage response, are needed.

Stopping Candida in its tracks

18 hours ago

Scientists are one step closer to understanding how a normally harmless fungus changes to become a deadly infectious agent.

New technique maps elusive chemical markers on proteins

Jul 02, 2015

Unveiling how the 20,000 or so proteins in the human body work—and malfunction—is the key to understanding much of health and disease. Now, Salk researchers developed a new technique that allows scientists ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.