src homology 2 [SH2] domain

Introduction

A group of related sequences 50-100 amino acids in length. SH2-domains bind to tyrosine phosphates with specificity of different SH2-domains for different phosphotyrosine motifs. Their probable function is to modulate protein-protein interactions of tyrosine-phosphorylated proteins, largely by colocalizing the proteins involved in the pTyr-SH2 interaction. The specificity of SH2-domains for specific tyrosine phosphates is determined by variable residues in the SH2-domain & residues C-terminal to the phosphorylated tyrosine.

Kd is 10-100 nM for high affinity binding. The only invariant residue in SH2 domains is an Arg which forms hydrogen bonds with 2 pTyr oxygens. The Arg is frequently contained within a FLVRES motif, a Ser phosphorylation site in which phosphorylation may inhibit SH2-pTyr interactions.

More general terms

• domain
• allosteric site
• cytoplasmic motif

Additional terms

• SH2 domain-containing protein
• src homology 3 [SH3] domain
• src proto-oncogene protein