NF155

NF155 is a glial isoform of the neural cell adhesion molecule neurofascin, encoded by the NFASC gene. It is one of several neurofascin isoforms, including NF186 and NF140, produced by alternative splicing. NF155 is predominantly expressed by myelinating glia—Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system—and localizes to the paranodal regions adjacent to the nodes of Ranvier.

In the paranode, NF155 interacts with axonal proteins Caspr1 and Contactin-1 to form the paranodal axo-glial junction. This complex helps organize and stabilize the node–paranode boundary, restricting the lateral diffusion of membrane components and maintaining the integrity of saltatory conduction along myelinated fibers.

Clinically, autoantibodies against NF155 have been identified in a subset of patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and related nodopathies. Patients with anti-NF155 antibodies may present with tremor, ataxia, and a reduced response to intravenous immunoglobulin therapy; plasma exchange or rituximab can be beneficial in some cases. Animal studies where NF155 function is disrupted show destabilization of paranodal junctions and impaired nerve conduction, underscoring NF155’s critical role in the proper functioning of myelinated axons.