Functions in cell-cell adhesion, cell migration and axon guidance, exerting an attractive or repulsive role depending on its interaction partners. Plays a role in the spatial organization of brain neurons. Plays a role in vascular development in the retina (By similarity). Plays a role in cell-cell adhesion via its interaction with ADGRL3 and probably also other latrophilins that are expressed at the surface of adjacent cells (By similarity). Interaction with the intracellular domain of ROBO1 mediates axon attraction towards cells expressing NTN1. Mediates axon growth cone collapse and plays a repulsive role in neuron guidance via its interaction with UNC5B, and possibly also other UNC-5 family members (By similarity). Promotes neurite outgrowth (in vitro). Mediates cell-cell contacts that promote an increase both in neurite number and in neurite length. Plays a role in the regulation of the density of glutamaergic synapses. Plays a role in fibroblast growth factor-mediated signaling cascades. Required for normal morphogenesis during embryonic development, but not for normal embryonic patterning. Required for normal ventral closure, headfold fusion and definitive endoderm migration during embryonic development. Required for the formation of a normal basement membrane and the maintenance of a normal anterior visceral endoderm during embryonic development (By similarity). Monomer and homodimer. Self-associates (via leucine-rich repeats), giving rise to homooligomers (By similarity). Interacts with FGFR1. Interacts (via extracellular domain) with ADGRL1/LPHN1 and LPHN2 (via olfactomedin-like domain) (By similarity). Interacts (via extracellular domain) with ADGRL3 (via olfactomedin-like domain); the interaction is direct. Interacts (via extracellular domain) with UNC5B and UNC5D (via extracellular domain); the interaction is direct. Identified in complexes composed of FLRT3, ADGRL3 and UNC5B, respectively FLRT3, ADGRL3 and UNC5D (By similarity). May also interact (via extracellular domain) with UNC5A and UNC5C. Interacts (via cytoplasmic domain) with ROBO1 (By similarity). Detected on dendritic punctae that colocalize in part with glutamaergic synapses, but not with GABAergic synapses. Proteolytic cleavage in the juxtamembrane region gives rise to a shedded ectodomain. N-glycosylated. Proteolytic cleavage in the juxtamembrane region gives rise to a soluble ectodomain. Cleavage is probably effected by a metalloprotease.