title: Construction of a soluble human GH-receptor/EGF-receptor hybrid and its activation by GH.
abstract: To develop a cell-free system that can be used to measure cytokine bioactivity we have designed a soluble hybrid molecule consisting of the extracellular domain of the GH-receptor (GHR) and the intracellular domain of the epidermal growth factor receptor (EGFR). A DNA construct encoding this hybrid-receptor was inserted into a baculoviral expression vector and expressed in Sf9-cells. Activation of the hybrid-receptor by ligand-induced dimerization can be measured as the incorporation of radiolabeled phosphate into a biotinylated tyrosine kinase peptide substrate. The kinase activity in samples stimulated with GH (10 ng/ml) increased 5-fold compared to samples without addition of GH. This is the first example of a functional hybrid-receptor where the transmembrane domain has been deleted. Our results suggest that such hybrid-receptors may be used for detection of GH and other cytokine-receptor activating substances in biological fluids.
authors.affiliation: Göteborg Pediatric Growth Research Centre, Department of Pediatrics, The Sahlgrenska Academy at Göteborg University, Göteborg, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Hellgren
authors.forename: C
authors.initials: C
authors.lastname: Löfqvist
authors.forename: K Albertsson
authors.initials: KA
authors.lastname: Wikland
authors.forename: B
authors.initials: B
authors.lastname: Carlsson
authors.forename: L M S
authors.initials: LM
authors.lastname: Carlsson
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D066246:ErbB Receptors / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013006:Growth Hormone / Q000494:pharmacology*; D006801:Humans; D011986:Receptors, Somatotropin / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D011986:Receptors, Somatotropin; D011993:Recombinant Fusion Proteins; D013006:Growth Hormone; D066246:ErbB Receptors