Figure 1

Time course of STAT3 activation by LEPRb tyrosine/phenylalanine mutants. A, Schematic representation of the LEPRb point mutants used in this study. The membrane-proximal box1/2 region binds the JAK family kinase and Tyr1138 (box3) mediates the activation of STAT3. B, RINm5F cells expressing WT or mutant LEPRb (FFY, FYY, YFY) were treated with leptin (20 ng/ml) for the times indicated (0 min, 15 min, 45 min, 75 min, 135 min, 255 min). Total cellular lysates were subjected to Western blot analysis and immunodetection with the indicated antibodies. These results are representative of 2 (YFY) or at least 3 (WT, FFY, FYY) independent experiments.