STIM Structure (IMAGE) La Jolla Institute for Immunology Caption This is a protein chemist's depiction of the calcium-sensing region in two engineered STIM1 protein variants. The sites that were altered are highlighted in each case as red spheres. The behavior of these two engineered proteins provided key insights into how STIM1 detects changes in calcium levels Credit Dr. Patrick Hogan, La Jolla Institute for Immunology 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.