Contributes to the regulation of axonal growth in the embryonic and adult central nervous system by inhibiting interactions between RTN4R and LINGO1. Inhibits RTN4R-mediated axon growth cone collapse (By similarity). May play an important role in regulating the production of neural crest cells by the neural tube (By similarity). May be required for normal responses to olfactory stimuli (By similarity). Homotetramer; disulfide-linked. Dimer of dimers, giving rise to a V-shaped homotretramer. Isoform 1 and isoform 3 interact with RTN4R. Identified in a complex with RTN4R and LINGO1. Peripherally associated with AMPAR complex. AMPAR complex consists of an inner core made of 4 pore-forming GluA/GRIA proteins (GRIA1, GRIA2, GRIA3 and GRIA4) and 4 major auxiliary subunits arranged in a twofold symmetry. One of the two pairs of distinct binding sites is occupied either by CNIH2, CNIH3 or CACNG2, CACNG3. The other harbors CACNG2, CACNG3, CACNG4, CACNG8 or GSG1L. This inner core of AMPAR complex is complemented by outer core constituents binding directly to the GluA/GRIA proteins at sites distinct from the interaction sites of the inner core constituents. Outer core constituents include at least PRRT1, PRRT2, CKAMP44/SHISA9, FRRS1L and NRN1. The proteins of the inner and outer core serve as a platform for other, more peripherally associated AMPAR constituents, including OLFM1. Alone or in combination, these auxiliary subunits control the gating and pharmacology of the AMPAR complex and profoundly impact their biogenesis and protein processing (By similarity). Interacts with OLFM2 (PubMed:21228389). Experimental confirmation may be lacking for some isoforms. The protein contains a globular N-terminal tetramerization domain, a long stalk formed by the coiled coil region and a C-terminal olfactomedin-like domain. Interactions between dimers are mediated by the coiled coil region. The dimers interact mostly via the N-terminal tetramerization domain, giving rise to a V-shaped overall architecture of the tetramer.