The long isoform consists of 1162 amino acids and is the only Leptin receptor isoform with clearly demonstrated signaling capability [1]. Leptin signaling occurs typically through the JAK/STAT pathway. Janus kinase 2 (JAK2) activation leads to tyrosine phosphorylation of Leptin receptor. Phosphorylated Tyr1138 of Leptin receptor serves as a binding site for STAT proteins.