Neural extracellular matrix (ECM) protein involved in interactions with different cells and matrix components. Involved in cell attachment and neurite formation. Interaction with CNTN1 enhances the neurite outgrowth. Forms homodimers and homotrimers. Interacts with CNTN1, NFASC and CSPG5. May be attach to the cell surface of neural cells. Brain specific. Expression weakly detectable at E6 embryo, reaches a maximum at E16 and declines in the adult. The N-terminus cysteine-rich segment may mediate the formation of oligomers. The fibronectin type-III 2-3 mediate the binding to contactin 1. The fibronectin type-III 9 mediates the cell attachment. The fibronectin type-III 2-5 mediate NFASC binding. The fibrinogen C-terminal domain mediates interaction with CSPG5. Belongs to the tenascin family.