ATF1 and obesity due to melanocortin 4 receptor deficiency: At the organismal level, PKD functions as a novel nutrient sensor391 and a major contributor to pathologies associated with obesity.392 Recent evidence indicates that the PKD family catalyzes CREB phosphorylation in PDAC cells stimulated by neurotensin.313 Consequently, obesity mediators and stress neurotransmitters stimulate protein kinase signaling pathways, including PKD and PKA, which converge on CREB/ATF1 phosphorylation in pancreatic cancer cells, as depicted schematically in Fig. 5.