Two signaling pathways that control axon guidance are the cyclic nucleotide-protein kinase A (PKA) pathway and a pathway controlled by plexin A, a guidance receptor that responds to the repulsive guidance cue semaphorin 1A. Terman and Kolodkin have determined that a single protein, nervy, links these two pathways in Drosophila neurons. Nervy is an A kinase-anchoring protein that binds to both PKA and to plexin A. When not bound to PKA, nervy antagonizes both axonal repulsion and plexin A signaling.
J. R. Terman, A. L. Kolodkin, Nervy links protein kinase A to Plexin-mediated semaphorin repulsion. Science 303, 1204-1207 (2004). [Abstract] [Full Text]