Rho GTPases and axonal growth cone collapse

This chapter describes Rho guanosine 5'-triphosphates (GTPases) and axonal growth cone collapse. The axonal growth cone is the specialized distal tip of the extending axon and consists of both lamellipodia and filopodia structures. Control of growth cone dynamics is critical for neurite outgrowth and guidance. Modulating the activity state of Rho, Rac, and Cdc42 in neurons can modulate the growth cone response to collapsing agents. The chapter discusses two methods of introducing Rho family GTPase into cultured neurons. These methods are designed to facilitate an analysis of the role of such GTPase in growth cone collapse by axonal guidance factors. The chapter presents a protocol to measure levels of activated Rac and Cdc42 in cultured neurons following the introduction of growth cone collapsing agents.