The interdependent roles of Ca²⁺ and cAMP in axon guidance

Axon guidance is a fundamental process in the developing and regenerating nervous system that is necessary for accurate neuronal wiring and proper brain function. Two of the most important second messengers in axon guidance are Ca²⁺ and cAMP. Recently experimental and theoretical studies have uncovered a Ca²⁺- and cAMP-dependent mechanism for switching between attraction and repulsion. Here, we review this process and related Ca²⁺ and cAMP interactions, the mechanisms by which necessary intracellular calcium elevations are created, and the pathways, which effect attractive and repulsive responses to the switch.