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Updated: Jul 10, 2026
High Yield Expression of Recombinant Human Proteins with the Transient Transfection of HEK293 Cells in Suspension
Published on: December 28, 2015
Expression, purification, and characterization of the cytoplasmic domain of the human IGF-1 receptor using a
N Tennagels1, C Hube-Magg, A Wirth
1Institute of Biochemistry, University of Cologne, Otto-Fischer-Strasse 12-14, Cologne, D-50674, Germany.
Abstract:
The cytoplasmatic domain of the beta-subunit of the human IGF-1 receptor (residues 929-1337) has been overexpressed in insect cells using the baculovirus expression system. Synthesis of the soluble protein (IGFK, M(r) 46 kDa) in Spodoptera frugiperda (Sf9) cells was detected 24 h after infection and maximal accumulation was achieved 40-48 h postinfection. Rapid purification to near homogeneity (>/=95% pure protein) was accomplished by sequential chromatography on Resource-Q and phenyl-Sepharose with a specific activity of 142 nmol/min/mg using poly[Glu:Tyr] as substrate. The purified IGFK showed a preference for Mn(2+) ions and a linear incorporation of (32)P from [gamma-(32)P]ATP over a 20-fold dilution of the protein and was stimulated 20-fold by the polycation poly-L-lysine. Interestingly, the kinase autophosphorylated on tyrosine and serine residues. In contrast, a kinase-negative mutant, IGFK-K1003A, did not undergo phosphorylation on tyrosine or serine residues, respectively, suggesting that IGF-1 receptor kinase is a dual specific kinase.
