Identification of the Y985 and Y1077 motifs as SOCS3 recruitment sites in the murine leptin receptor

The leptin system provides a link between adipose mass and the central nerv ous system. The appetite suppressing effects of leptin are impaired in most obese patients and some mutant mice strains. Herein,ve describe how suppre ssor of cytokine signalling 3 (SOCS3), a potential mediator of this leptin resistance is recruited into the activated murine leptin receptor complex. Using a functional assay based on inhibition of leptin mediated reporter in duction, and using phosphopeptide affinity chromatography we show binding o f SOCS3 to the highly conserved phosphorylated Tyr-985 and Tyr-1077 motifs within the mouse leptin receptor. (C) 2000 Federation of European Biochemic al Societies. Published by Elsevier Science B.V. All rights reserved.