Ligand for NRCAM and NFASC/neurofascin that plays a role in the formation and maintenance of the nodes of Ranvier on myelinated axons. Mediates interaction between Schwann cell microvilli and axons via its interactions with NRCAM and NFASC (PubMed:16039564). Nodes of Ranvier contain clustered sodium channels that are crucial for the saltatory propagation of action potentials along myelinated axons. During development, nodes of Ranvier are formed by the fusion of two heminodes. Required for normal clustering of sodium channels at heminodes; not required for the formation of mature nodes with normal sodium channel clusters. Required, together with NRCAM, for maintaining NFASC and sodium channel clusters at mature nodes of Ranvier (By similarity). Homotrimer (via collagen-like domains) (PubMed:17485493) (Probable). Interacts with NRCAM (PubMed:16039564, PubMed:22009740). Interacts with NFASC/neurofascin (PubMed:16039564, PubMed:17485493, PubMed:22009740). Interaction with glial NRCAM enhances interaction with axonal NFASC. Interacts with MYOC (By similarity). Detected at the nodes of Ranvier (PubMed:16039564, PubMed:22009740). Detected at immature heminodes (PubMed:22009740). Proteolytic processing gives rise to a soluble extracellular domain that is secreted. The gliomedin shedded ectodomain localizes to the nodes of Ranvier. Detected in Schwann cells (at protein level). Expression increases in myelinating Schwann cells during the initial period of active myelination. The olfactomedin-like domain mediates NFASC/neurofascin and NRCAM binding. N-glycosylated. Proteolytic proccessing by a furin-like protease causes shedding of the ectodomain (PubMed:17485493). Further cleavage by BMP1 releases the olfactomedin-like domain.