Functions as an activator subunit for the CBK1 protein kinase. Part of the regulation of ACE2 activity and cellular morphogenesis (RAM) signaling network. The RAM network is critically required for hyphal growth as well as normal vegetative growth, and for polarization of lipid rafts and the actin cytoskeleton. It play an essential role in biofilm formation. The RAM network also plays a role in serum- and antifungal azoles-induced activation of ergosterol biosynthesis genes, especially those involved in the late steps of ergosterol biosynthesis. Interacts with protein kinase CBK1 to form the RAM CBK1-MOB2 kinase complex. localizes to sites of polarized growth in both yeast and hyphal cells. Phosphorylated by CDC28 at Ser-44, Ser-51, Ser-67, and Ser-97. Phosphorylation occurs during bud emergence and is maintained until the G2/M transition. Dephosphorylated at the end of mitosis. Phosphorylation is required for the maintenance of polarisome components in hyphae. Leads to hypersensitivity to cell-wall- or membrane-perturbing agents, cell-separation defects, a multinucleate phenotype, and loss of cell polarity. Belongs to the MOB1/phocein family.