Multifunctional protein that functions as a downstream effector of RALA and RALB. As a GTPase-activating protein/GAP can inactivate CDC42 and RAC1 by stimulating their GTPase activity (PubMed:7623849, PubMed:9422736). As part of the Ral signaling pathway, may also regulate ligand-dependent EGF and insulin receptors-mediated endocytosis (PubMed:10393179). During mitosis, may act as a scaffold protein in the phosphorylation of EPSIN/EPN1 by the mitotic kinase cyclin B-CDK1, preventing endocytosis during that phase of the cell cycle. During mitosis, also controls mitochondrial fission as an effector of RALA. Recruited to mitochondrion by RALA, acts as a scaffold to foster the mitotic kinase cyclin B-CDK1-mediated phosphorylation and activation of DNM1L (By similarity). Could also function as a primary ATP-dependent active transporter for glutathione conjugates of electrophiles. May also actively catalyze the efflux of a wide range of substrates including xenobiotics like doxorubicin (DOX) contributing to cell multidrug resistance. an S-substituted glutathione(in) + ATP + H2O = ADP + an S-substituted glutathione(out) + H(+) + phosphate ATP + H2O + xenobioticSide 1 = ADP + phosphate + xenobioticSide 2. ATP + H2O + leukotriene C4(in) = ADP + H(+) + leukotriene C4(out) + phosphate Interacts with the GTP-bound form of RALA (via effector domain); during mitosis, recruits RALBP1 to the mitochondrion where it promotes DNM1L phosphorylation and mitochondrial fission (PubMed:7623849). Interacts with DNM1L; mediates its mitotic kinase cyclin B-CDK1-mediated phosphorylation during mitosis to promote mitochondrial fission. Interacts with the mitotic kinase cyclin B-CDK1 during mitosis. Interacts with the GTP-bound form of RALB (via effector domain) (By similarity). Interacts with REPS1; the interaction is direct and does not affect RALA-binding nor GTPase activator activity of RALBP1 (PubMed:9395447). Interacts with REPS2; the interaction is direct and does not affect RALA-binding nor GTPase activator activity of RALBP1 (PubMed:9422736). Interacts with EPN1, NUMB and TFAP2A during interphase and mitosis. Interacts with AP2M1; as part of the AP2 complex. Interacts with CDC42. Interacts with RAC1 (By similarity). Cytosolic protein that transiently associates with the mitotic spindle poles in early prophase, and dissociates from them after completion of mitosis (PubMed:9973605). Targeted to the plasma membrane through its interaction with RALB, directed by FGF signaling. Docking on the membrane is required to transduce the Ral signal (By similarity). Recruited by RALA to the mitochondrion during mitosis where it regulates mitochondrial fission. Nuclear localization is cell cycle dependent while membrane localization is seen in adherent cells. The region involved in membrane association could form transmembrane domains and expose a part of the protein extracellularly (By similarity). Ubiquitously expressed. The Rho-GAP domain mediates the GTPase activator activity toward CDC42. Tyrosine-phosphorylated upon stimulation of cells with EGF. May undergo proteolytic cleavage to give peptides which reassemble to form a transporter complex.