14‐3‐3 binding to the IGF‐1 receptor is mediated by serine autophosphorylation1

FEBS Letters

Baer, Kristin¹  Al-Hasani, Hadi²  Klein, Helmut W¹  Yesilkaya, Tanju¹  Parvaresch, Susan¹ 

[1]Institute of Biochemistry, University of Cologne, Otto-Fischer-Str. 12–14, 50674 Cologne, Germany

[2]German Institute for Human Nutrition, Potsdam–Rehbrücke, Germany

关键词: Insulin-like growth factor-1 receptor;    Dual kinase activity;    Serine autophosphorylation;    14-3-3;    Protein–protein interaction;    GST;    glutathione S-transferase;    IGF-1R;    insulin-like growth factor-1 receptor;    IGFKD;    soluble insulin-like growth factor-1 receptor kinase domain;    Sf9;    Spodoptera frugiperda;    SDS–PAGE;    sodium dodecyl sulfate–polyacrylamide gel electrophoresis;    PVDF;    polyvinyl difluoride;    ECL;    enhanced chemiluminescence;   

DOI  :  10.1016/S0014-5793(02)03708-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The phosphoserine-binding 14-3-3 proteins have been implicated in playing a role in mitogenic and apoptotic signaling pathways. Binding of 14-3-3 proteins to phosphoserine residues in the C-terminus of the insulin-like growth factor-1 receptor (IGF-1R) has been described to occur in a variety of cell systems, but the kinase responsible for this serine phosphorylation has not been identified yet. Here we present evidence that the isolated dimeric insulin-like growth factor-1 receptor kinase domain (IGFKD) contains a dual specific (i.e. tyrosine/serine) kinase activity that mediates autophosphorylation of C-terminal serine residues in the enzyme. From the total phosphate incorporation of ∼4 mol per mol kinase subunit, 1 mol accounts for serine phosphate. However, tyrosine autophosphorylation proceeds more rapidly than autophosphorylation of serine residues (t _1/2∼1 min vs. t _1/2∼5 min). Moreover, dot-blot and far-Western analyses reveal that serine autophosphorylation of IGFKD is sufficient to promote binding of 14-3-3 proteins in vitro. The proof that dual kinase activity of IGFKD is necessary and sufficient for 14-3-3 binding was obtained with an inactive kinase mutant that was phosphorylated on serine residues in a stoichiometric reaction with the catalytically active enzyme. Thus, the IGF-1R itself might be responsible for the serine autophosphorylation which leads to recognition of 14-3-3 proteins in vivo.

【 授权许可】

Unknown