Lrpap1 also known as Alpha-2-macroglobulin receptor-associated protein. The alpha-2-macroglobulin receptor-associated protein (RAP) is a glycoprotein that binds to the alpha-2-macroglobulin receptor, as well as to other members of the low density lipoprotein receptor family. Lrpap1 acts to inhibit the binding of all know ligands for these receptors, and may prevent receptor aggregation and degradation in the endoplasmic reticulum, thereby acting as a molecular chaperone. Lrpap1 may be under the regulatory control of calmodulin, since it is able to bind calmodulin and be phosphorylated by calmodulin-dependent kinase II. Recombinant mouse Lspap1, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.