Cell surface receptor for SEMA4C, SEMA4D and SEMA4G that plays an important role in cell-cell signaling (PubMed:17554007). Plays a role in glutamatergic synapse development and is required for SEMA4A-mediated excitatory synapse development (PubMed:29981480). Binding to class 4 semaphorins promotes downstream activation of RHOA and phosphorylation of ERBB2 at 'Tyr-1248' (PubMed:17554007). Required for normal differentiation and migration of neuronal cells during brain corticogenesis and for normal embryonic brain development (PubMed:19948886). Regulates the migration of cerebellar granule cells in the developing brain (PubMed:21122816). Plays a role in RHOA activation and subsequent changes of the actin cytoskeleton (By similarity). Plays a role in axon guidance, invasive growth and cell migration (By similarity). May modulate the activity of RAC1 and CDC42 (PubMed:21966369). Down-regulates macrophage migration in wound-healing assays (in vitro) (PubMed:21966369). Monomer, and heterodimer with PLXNB1 (By similarity). Interacts with MET, ARHGEF11 and ARHGEF12 (By similarity). May also interact with MST1R (By similarity). Interacts with SEMA4C (PubMed:17554007, PubMed:21122816). Interacts with SEMA4D (PubMed:17554007). Interacts with SEMA4G (PubMed:21122816). Detected in macrophages from spleen and bone marrow (at protein level) (PubMed:21966369). Detected in granule cells in the developing cerebellum, dentate gyrus and olfactory bulb (PubMed:17554007). Expressed in neurons and glia in the developing hippocampus (PubMed:29981480). Embryonic and perinatal lethality, due to defects in brain and neural tube development. Mice exhibit abnormal cortical layering and defective migration and differentiation of several subtypes of cortical neurons. Cranial neural folds fail to converge in most embryos, leading to an open neural tube and exencephaly. Likewise, mice exhibit defects in the embryonic development of the cerebellum and the olfactory bulb. Belongs to the plexin family.