Module 6: Figure IRS domain structure
Domain structure of the insulin receptor substrate (IRS).
There are three insulin receptor substrate (IRS) isoforms. The domain structures of the main IRS1 and IRS2 isoforms illustrate the position of the phosphotyrosine-binding (PTB) domain and the pleckstrin homology (PH) domain. The latter is unusual in that it has a low affinity for lipids, but resembles the structure of PTB. The sequence motifs are potential tyrosine phosphorylation sites that enable IRS to recruit various signalling molecules. A typical example is PtdIns 3-kinase, which associates with IRS through its Src homology 2 (SH2) domains (Module 2: Figure insulin receptor).