PTPN1 and obesity due to melanocortin 4 receptor deficiency: Overall, a large body of compelling evidence indicates that PTP1B deletion or inhibition can be an effective strategy to improve glucose homeostasis, control body weight, and prevent hyperglycemia-induced complications, thus prompting the search for PTP1B inhibitors as novel antidiabetic and anti-obesity agents [3,10,25,32,33,34].