PTPN1 and obesity due to melanocortin 4 receptor deficiency: Dodd et al. recently report that a combined action of leptin and insulin on POMC neurons promotes WAT browning and energy expenditure and prevents diet-induced obesity through protein tyrosine phosphatase 1B (PTP1B) and T cell protein tyrosine phosphatase (TCPTP) signaling as deletion of the phosphatases PTP1B and TCPTP enhanced insulin and leptin signaling in POMC neurons (80).