The experimental simulation of gauge potentials and spin-orbit couplings in ultracold atomic gases paves the way to realize intriguing topological phases in these physical setups. In this talk I will describe how the interplay between synthetic magnetic fields and spin-orbit couplings allows to simulate topological insulators in optical lattices. I will analyse some example of topological phase transitions in these systems and I will examine possible experimental signatures of the non-trivial topological phases.