Fig. 8.

Model of neuronostatin signaling in pancreatic α-cells. Activation of GPR107 by neuronostatin results in the signaling of an unknown G protein, leading to the downstream activation of IKK. IKK phosphorylates IκBα, targeting it for degradation by the proteasome. Dissociation of IκBα releases the NF-κB complex (Rel A and p50), and the NF-κB-associated pool of PKA. The catalytic subunit of PKA is thus exposed, allowing activation and downstream phosphorylation events that ultimately lead to the transcription of proglucagon mRNA.