Main Page | See live article | Alphabetical index Calreticulin is a protein that binds Ca2+ ions (a second messenger molecule in signal transduction), rendering it inactive. The Ca2+ is bound with low affinity, but high capacity, and can be released on a signal (see inositol triphosphate). Calreticulin is located in storage compartments associated with the endoplasmic reticulum. Calreticulin is also known as calregulin, CRP55, CaBP3, calsequestrin-like protein and Ro/SS-A antigen. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.