Insulin modulates leptin‐induced STAT3 activation in rat hypothalamus

FEBS Letters

Siloto, Rodrigo M.P.¹  Carvalho, Carla R.O.²  Carvalheira, José B.C.²  Ignacchitti, Inara²  Brenelli, Sigisfredo L.²  Gontijo, José A.R.²  Leite, Adilson¹  Velloso, Lı́cio A.²  Saad, Mario J.A.² 

[1] Centro de Biologia Molecular e Engenharia Genética, CBMEG, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil;Departamento de Clı́nica Médica, FCM, Universidade Estadual de Campinas (UNICAMP), CP 6111, 13081-970 Campinas, SP, Brazil

关键词: Leptin;    Insulin;    Tyrosine phosphorylation;    Janus kinase 2;    Signal transducer and activator of transcription;    Long form of the leptin receptor;    IR;    insulin receptor;    IRS;    insulin receptor substrate;    OBR;    long form of the leptin receptor;    JAK2;    Janus kinase 2;    STAT3;    signal transducer and activator of transcription;    SH2;    src homology 2;    SHP-2;    phosphotyrosine phosphatase 2;    PI 3-kinase;    phosphatidylinositol 3-kinase;    EMSA;    electrophoretic mobility shift assay;   

DOI  :  10.1016/S0014-5793(01)02591-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Insulin and leptin have overlapping effects in the control of energy homeostasis, but the molecular basis of this synergism is unknown. Insulin signals through a receptor tyrosine kinase that phosphorylates and activates the docking proteins IRSs (insulin receptor substrates), whereas the leptin receptor and its associated protein tyrosine kinase JAK2 (Janus kinase 2) mediate phosphorylation and activation of the transcription factor STAT3 (signal transducer and activator of transcription). Here, we present evidence for the integration of leptin and insulin signals in the hypothalamus. Insulin induced JAK2 tyrosine phosphorylation, leptin receptor phosphorylation which, in the presence of leptin, augmented the interaction between STAT3 and this receptor. Insulin also increased the leptin-induced phosphorylation of STAT3 and its activation. These results indicate that insulin modulates the leptin signal transduction pathway, and may provide a molecular basis for the coordinated effects of insulin and leptin in feeding behavior and weight control.

【 授权许可】

Unknown