Abstract

The “Human Genome Project” was completed in 2003, shifting the focus to proteome and transcriptome research. One approach to proteomics involves the comprehensive visualization of the localization of proteins in all tissues and organs. We discuss in situ phospho‐protein atlases, which are systematized representations of the localization of proteins. Protein atlases provide important information about the identity and presence of proteins in specific organs, tissues and cells under physiological and pathological conditions. Antibody‐based immunohistochemical analysis is a powerful method for generating a protein atlas. However, it is difficult to localize phosphorylated proteins under in vivo physiological conditions, even with immunohistochemistry, because these proteins tend to be dephosphorylated or phosphorylated due to the experimental manipulations. We also discuss an improved immunohistochemical method for precisely detecting phosphorylated protein, using the detection of phosphorylated ERK1/2 as an example. We consider that it is possible and useful to generate a phospho‐protein atlas.