Molecular Portrait Reveals Cell Signaling Activity

Scientists from Stanford University in California headed by Brian Kobilka have finally revealed the structure of of G-protein-coupled receptors (GPCRs), which are involved in biology's most significant signaling mechanisms. After studying this for 20 years they have revealed a three-dimensional atomic structure of an activated GPCR in a complex with its G protein.

GPCRs are located in the cell membranes throughout the human body, where they function as detectors from the external world, waiting for signals like light, odor, and flavor, as well as signals inside the body like hormones and neurotransmitters. Once the signals are recognized, GPCRs activate intracellular G proteins, which then trigger different biochemical pathways.

The structure now explains how G protein's mouth splays wide open when the molecule guanosine diphosphate (GDP) departs. When a GPCR receives a signal, the receptor forces the G protein to throw out the GDP, allowing a molecule of guanosine triphosphate to swoop in and turn on the G protein.

"This is a real breakthrough paper," says biochemist Stephen Sprang at the University of Montana in Missoula. "For a long time, many folks in the field have considered this the hoped-for structure that would ultimately provide a real understanding of how the receptors actually work."

For more details, read the original article at http://www.nature.com/news/2011/110719/full/475273a.html.