Receptor for SEMA4D (PubMed:19843518, PubMed:20877282, PubMed:21912513). Plays a role in GABAergic synapse development (By similarity). Mediates SEMA4A- and SEMA4D-dependent inhibitory synapse development (By similarity). Plays a role in RHOA activation and subsequent changes of the actin cytoskeleton (PubMed:12196628, PubMed:15210733). Plays a role in axon guidance, invasive growth and cell migration (PubMed:12198496). Monomer, and heterodimer with PLXNB2 after proteolytic processing (PubMed:12533544, PubMed:17916560, PubMed:18411422, PubMed:18275816, PubMed:19843518, PubMed:20877282, PubMed:21912513). Binds RAC1 that has been activated by GTP binding (PubMed:11035813, PubMed:17916560, PubMed:18275816, PubMed:19843518). Interaction with SEMA4D promotes binding of cytoplasmic ligands (PubMed:10520995, PubMed:12198496, PubMed:19843518). Interacts with PLXNA1 (By similarity). Interacts with ARHGEF11 and ARHGEF12 (PubMed:12196628). Interacts with ERBB2 (PubMed:15210733). Interacts with MET (PubMed:12198496, PubMed:15184888). Interacts with MST1R (PubMed:15184888). Interacts with RRAS (PubMed:19843518). Interacts with RHOD (PubMed:17916560). Interacts with RND1 (PubMed:12730235, PubMed:17916560, PubMed:18275816, PubMed:19843518). Interacts with NRP1 and NRP2 (PubMed:10520995). Highly expressed in fetal kidney, and at slightly lower levels in fetal brain, lung and liver. Phosphorylated on tyrosine residues by ERBB2 and MET upon SEMA4D binding. Proteolytic processing favors heterodimerization with PLXNB2 and SEMA4D binding. Belongs to the plexin family. Extended N-terminus.