Figure 2.

Mechanisms of leptin signaling. Upon leptin binding to Ob-Rb, the Janus kinase/signal transducer and activator of transcription (JAK/STAT), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3-kinase (PI3K) pathways are activated. Akt, protein kinase B; Grb-2, growth receptor-bound-2; IRS, insulin receptor substrate; MEK, mitogen-activated protein kinase kinase; PIAS 3, protein inhibitor of activated STAT3; Raf, MEK-kinase; Ras, G-protein; SHP-2, SH2-domain containing protein tyrosine phosphatase; SOCS3, suppressor of cytokine signalling-3.