Fig. 2From: PhosphOrtholog: a web-based tool for cross-species mapping of orthologous protein post-translational modificationsSoftware architechture. The four layers of the software implementation procedure and the communications between the layers are illustrated. The storage layer shows the six reference ortholog mapping databases where the species are abbreviated by their first letter, for e.g. human by H, rat by R, mouse by M and fly by F. The database of annotated PTM sites obtained from PhosphoSitePlus is represented as PSPBack to article page