An SH2 domain is a protein domain that mediates specific protein interactions. The abbreviation stands for SH2 Src homology 2 (derived from the protein kinase c- Src, in which the domain was described for the first time; see SH3 domain ). The region is about 100 amino acids long and specifically recognizes peptides with phosphorylated tyrosine. SH2 domains are involved in many protein complexes, in particular for scaffolding proteins. In addition, SH2 domains play an important role in several signaling pathways.