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PROSITE documentation PDOC00212 [for PROSITE entry PS00239] |
A number of growth factors stimulate mitogenesis by interacting with a family of cell surface receptors which possess an intrinsic, ligand-sensitive, protein tyrosine kinase activity [1]. These receptor tyrosine kinases (RTK) all share the same topology: an extracellular ligand-binding domain, a single transmembrane region and a cytoplasmic kinase domain. However they can be classified into at least five groups. The prototype for class II RTK's is the insulin receptor, a heterotetramer of two α and two β chains linked by disulfide bonds. The α and β chains are cleavage products of a precursor molecule. The α chain contains the ligand binding site, the β chain transverses the membrane and contains the tyrosine protein kinase domain. The receptors currently known to belong to class II are:
And the following uncharacterized receptors:
While only the insulin and the insulin growth factor I receptors are known to exist in the tetrameric conformation specific to class II RTK's, all the above proteins share extensive homologies in their kinase domain, especially around the putative site of autophosphorylation. Hence, we developed a signature pattern for this class of RTK's, which includes the tyrosine residue, itself probably autophosphorylated.
Last update:November 1997 / Text revised.
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PROSITE method (with tools and information) covered by this documentation:
1 | Authors | Yarden Y. Ullrich A. |
Title | Growth factor receptor tyrosine kinases. | |
Source | Annu. Rev. Biochem. 57:443-478(1988). | |
PubMed ID | 3052279 | |
DOI | 10.1146/annurev.bi.57.070188.002303 |