Acts as guanine nucleotide exchange factor (GEF) for RhoA GTPase. May be involved in activation of the SAPK/JNK pathway. Stimulates genotoxic stress-induced RHOB activity in breast cancer cells leading to their cell death. Interacts with RHOA in its GTP- and GDP-bound states, and with CDC42 in its GTP-bound state. Interacts with the PDZ 1 domain of BAIAP1. The PH domain is sufficient for the nuclear export of the oncogenic N-terminal truncated form. The relocalization is not affected by the Leu-492 mutation. Can be converted to an oncogenic protein by N-terminal deletion that leads to nuclear export and cytoplasmic localization. Transformation seems to require the activity of multiple signaling pathways. The physiological conditions for cytoplasmic relocalization are not known yet.