Plexins: making links to the cytoskeleton and reducing the GAPs in our knowledge

Abstract

During development of the nervous system, the establishment of axonal projections requires tight control of the extraordinarily complex machinery of growth cones — the specialized axonal structures enabling pathway selection. The discovery of several families of guidance molecules displaying attractive and repulsive properties provided new insights into the molecular nature of axonal guidance. Among these guidance factors, the functions of different members of the semaphorin family have been well characterized. In particular, semaphorin 3A (Sema3A) is a potent inducer of growth cone collapse by a mechanism that results in the depolymerization of F-actin. Several studies have demonstrated the involvement of a receptor complex for the transduction of the Sema3A signal. It appears that the first-reported receptor, neuropilin-1, acts as a ligand-binding subunit requiring additional receptor components such as members of the plexin family for signal transduction.