The Atomic Structure of the SOS pProtein (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption The atomic structure of the SOS protein, a cell messaging molecule that uses a unique timing mechanism to regulate activation of a critical immune system pathway. Credit Credit: Steven Alvarez/Berkeley Lab Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.