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A third fibronectin type III domain in the extracellular region of the insulin receptor family
Author(s) -
Marino-Buslje Cristina,
Mizuguchi Kenji,
Siddle Kenneth,
Blundell Tom L.
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01509-9
Subject(s) - fibronectin , insulin receptor , insulin like growth factor 1 receptor , receptor tyrosine kinase , extracellular , biology , chemistry , receptor , microbiology and biotechnology , biochemistry , insulin , extracellular matrix , insulin resistance , endocrinology , growth factor
The insulin receptor family consists of the homologous tyrosine kinase receptors, insulin receptor (IR), insulin‐like growth factor 1 receptor (IGF1R) and insulin receptor‐related receptor. The three‐dimensional structures of the tyrosine kinase domain of the IR and the first three extracellular domains (L1, Cys‐rich and L2) of the IGF1R are known. Here we present evidence that the connecting domain of the IR family is a member of the fibronectin type III (FnIII) superfamily. Structure‐based alignment of FnIII domains reveals several key residues that are also conserved in the sequence of the connecting domain. The alignment of the connecting domain with FnIII domains is in good agreement with secondary structure prediction. A model of the connecting domain shows a hydrophobic core formed by the conserved residues and is consistent with previously known biochemical data. This suggests that the IR family contains three FnIII domains in tandem in the extracellular juxtamembrane region.