Olfactory marker protein (OMP),a member of the olfactory marker protein family, is also known as olfactory neuronal-specific protein, which is uniquely associated with mature olfactory receptor neurons. OMP can interact with BEX1 and BEX2.OMP may act as a modulator of the olfactory signal-transduction cascade. Furthermore, immunocytochemical analysis has demonstrated that expression of the olfactory marker protein (OMP) is highly restricted to mature olfactory receptor neurons in virtually all vertebrate species from fish to man.