Effect of receptor phosphorylation on the binding between IRS-1 and IGF-1R as revealed by surface plasmon resonance biosensor.
A receptor binding assay based on the surface plasmon resonance (SPR) biosensor technique was developed to study the interaction between insulin-like growth factor-1 receptor (IGF-1R) and its intracellular substrate protein insulin receptor substrate-1 (IRS-1). The sensor surface was modified with anti-IGF-1R (alpha-subunit) monoclonal antibodies for the capturing of the receptor-containing membrane fragments from cell lysates. The IGF-1R was successfully immobilized on the sensor surface with binding capability for its intracellular substrates. SPR measurements showed that the tyrosine phosphorylation of IGF-1R induced by its extracellular ligand insulin-like growth factor-1 caused the receptor to bind with IRS-1 10 times faster than the unactivated receptor. As a result, the affinity constants of IRS-1 to phosphorylated and unphosphorylated IGF-1R were (8.06+/-5.18)x10(9) M(-1) and (9.81+/-4.61)x10(8) M(-1), respectively.
Huang
M
M
Department of Biology and Chemistry, City University of Hong Kong, Kowloon, PR China.
Lai
W P
WP
Wong
M S
MS
Yang
M
M
D016475:3T3 Cells / Q000187:drug effects; D000818:Animals; D003432:Cross-Linking Reagents / Q000737:chemistry; D055504:Insulin Receptor Substrate Proteins; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D010750:Phosphoproteins / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D017526:Receptor, IGF Type 1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020349:Surface Plasmon Resonance / Q000379:methods*
D003432:Cross-Linking Reagents; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; D010750:Phosphoproteins; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1