The activity of Rho GTPases must be carefully regulated to allow them to control a variety of cellular processes. Spatiotemporal control of Rho activation depends, in part, on different guanine-nucleotide-exchange factors (GEFs). Here, Joseph Gray and co-workers (p. 2721) dissect the functional specialisation of two RhoGEFs, Rom2 and Tus1, in budding yeast. Using mutant strains lacking Rom2 and Tus1, respectively, they show that the two GEFs differentially activate Rho1 effector pathways: whereas Rom2 is more important for the activation of glucan synthase and the yeast protein kinase C homologue Pkc1, Tus1 has a more prominent role in activating the Rho1–Yfc1 pathway. In addition, the loss of Rom2, or its closely related homologue Rom1, cannot be rescued by the overexpession of Tus1. The researchers also address whether the functional specialisation of these GEFs is a result of differences in their localisation. They find that Rom2 localises to the bud neck and bud cortex in an Ack1-dependent manner. By contrast, Tus1 localisation specifically depends on the association of this GEF with the previously unidentified protein Ypl066w (Rgl1). Together, these observations highlight that the RhoGEFs not only act in distinct cellular compartments, but that they can achieve functional specialisation through the activation of distinct Rho effector pathways.