Introduction -- FASTA -- BLAST -- Modular Domain -- Multiple Sequence Alignment -- PDB -- Summary

Modular domain identification

Pfam sequence analysis for homo sapien insulin receptor gave the following significant matches: 2 Receptor L domains, Furin-like cysteine rich region, Fibronectin type III domain, Protein tyrosine kinase

Uniprot sequence analysis showed the following domains: Topological Extracellular domain, Topological Cytoplasmic domain, Fibronectin type-III 1 domain, Fibronectin type-III 2 domain, Fibronectin type-III 3 domain, Protein kinase domain, ATP binding domain, IRS1- and SHC1-binding domain and a PIK3R1-binding domain.

Entrez protein sequence analysis shows the domains: 2 Receptor L domains, 2 Furin-like cysteine rich region, Fibronectin type 3 domain, Protein Tyrosine Kinase (PTKc_InsR) and SH2 domain.

Protein tyrosine kinase C domain

This protein kinase is from a large family of seventeen different protein kinases. It is formed of two alphabeta heterodimers. Its function is to transfer the gamma phosphate of ATP to an amino acid on a peptide substrate giving a conformational change in the molecule.

Fibronectin domains

This is a glycoprotein found on cell surface receptors. There are three types of these domains found on the insulin receptor, type I, II and III. Type III is the domain that received most hits on the search sites. This exists in three possible locations: at the C-terminal half of the monomers of insulin and a third exists between the L domain and these C-terminal fibronectin domains (1). It is a heterodimer joined by disulphide bonds. This repeat region, is one hundred amino acids long.

Receptor L domain

L domain is composed of a single beta helix with a Cys-rich area forming many disulphide bonds. The function of this domain is unknown.