Rac3 inhibits adhesion and differentiation of neuronal cells by modifying GIT1 downstream signaling.

Rac1 and Rac3 are highly homologous regulatory proteins that belong to the small GTPases of the Rho family. Previously, we showed that Rac3 induces cell rounding and prevents neuronal differentiation, in contrast to its close relative Rac1, which stimulates cell spreading and neuritogenesis. To explain these opposing effects, we investigated whether Rac1 and Rac3 interact with different proteins.