The leptin system provides a link between adipose mass and the central nervous system. The appetite suppressing effects of leptin are impaired in most obese patients and some mutant mice strains. Herein we describe how suppressor 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 induction, and using phosphopeptide affinity chromatography we show binding of SOCS3 to the highly conserved phosphorylated Tyr-985 and Tyr-1077 motifs within the mouse leptin receptor.
