Enables chemorepellent activity and fibroblast growth factor receptor binding activity. Involved in several processes, including fibroblast growth factor receptor signaling pathway; proepicardium cell migration involved in pericardium morphogenesis; and synapse organization. Acts upstream of or within positive regulation of synapse assembly. Located in several cellular components, including axonal growth cone; cell-cell junction; and glutamatergic synapse. Is integral component of postsynaptic membrane. Colocalizes with focal adhesion. Is expressed in several structures, including alimentary system; brain; embryo ectoderm; embryo mesenchyme; and eye. Human ortholog(s) of this gene implicated in hypogonadotropic hypogonadism 21 with or without anosmia. Orthologous to human FLRT3 (fibronectin leucine rich transmembrane protein 3). [provided by Alliance of Genome Resources, Apr 2022]