Probable cell surface receptor that regulates oligodendroglial precursor cell migration (By similarity). Might also regulate differentiation of oligodendroglial precursor cells (By similarity). Has growth cone collapse activity against retinal ganglion-cell axons (By similarity). Interacts (via PDZ-binding motif) with DLG4/SAP90 (via PDZ domain 2); this interaction may promote translocation of DLG4/SAP90 to the membrane. Colocalizes with DLG4 at synapses. Belongs to the semaphorin family.