INSR and obesity due to melanocortin 4 receptor deficiency: MSI-1436 selectively inhibits PTP1B and enhances insulin-stimulated tyrosine phosphorylation of insulin receptors, causing fat-specific weight loss in DIO mice.502 DPM-1001 is an analogue of MSI-1436, which can enhance β-subunit phosphorylation and reduce diet-induced obesity.503