From ScienceDaily:
Ras is a family of membrane-anchored proteins whose activation is a critical step in cellular signaling, but almost everything we know about how Ras signals are activated has been derived from bulk assays, in solution or in live cells, in which information about the role of the membrane environment and anything about variation among individual molecules is lost," says Jay Groves, a chemist with Berkeley Lab's Physical Biosciences Division and UC Berkeley's Chemistry Department. "Using a supported-membrane array platform, we were able to perform single molecule studies of Ras activation in a membrane environment and discover a surprising new mechanism though which Ras signaling is activated by Son of Sevenless (SOS) proteins.
Specifically:
For cellular signaling networks involving large numbers of protein molecules, the outcome can be directly determined by the process of averaging. Even though the behavior of an individual protein is intrinsically variable, the average behavior from a large group of identical proteins is precisely determined by molecular level probabilities. Ras activation in a living cell, however, involves a relatively small number of SOS molecules, making it impossible to average the variable behavior of the individual molecules. This variation is referred to as stochastic "noise" and has been widely viewed by scientists as an error a cell must overcome.
"Our study showed that, in fact, an important aspect of the SOS signal that activates Ras is encoded in the noise," says Groves. "The protein's dynamic fluctuations between different states of activity transmit information, which means we have found a regulatory coupling in a protein signaling reaction that is entirely based on dynamics, without any trace of the signal being seen in the average behavior."
(Score: 1) by maxim on Sunday July 06 2014, @04:34PM
Chrome or Chromium?
(Score: 2) by SlimmPickens on Sunday July 06 2014, @04:47PM
Well that all depends on your SOS protein levels.
(Score: 2) by bugamn on Tuesday July 08 2014, @01:53AM
I thought it depended whether you wanted to use Google's compiled version or the open-source alternative that is in most distros' repositories.
(Score: 1) by LAngeOliver on Monday July 07 2014, @01:08AM
I'm surprised to see a story of that complexity being exposed on SN. Sure beats having to read through hundreds of abstract to find useful stuff.
Decode your health [biogeniq.ca]