Schematic representation of NPF2/PKA/CREB-B/NOS signaling cascade in the modulation of locomotor plasticity in the locust.

During isolation, the up-regulation of NPF2 signal suppresses the NOS transcription by inhibiting CREB-B phosphorylation catalyzed by PKA, thus reducing locomotor activity. Upon crowding, the down-regulation of NPF2 signal promotes PKA activity, which in turn activates CREB-B phosphorylation and NOS transcription and consequently enhanced locomotor activity. Blue dots in the locust brain indicate NPF2 localization. Bold indicates increased levels or activity.