Human Contactin 2 (CNTN2) Protein

Background

Contactin 2 (CNTN2), also known as TAG-1 (Transient Axonal Glycoprotein 1), is another GPI-anchored neural adhesion molecule involved in axonal guidance, synaptic development, and neuron-glia interactions. CNTN2 is predominantly expressed during development in the central and peripheral nervous systems, where it plays a critical role in axon fasciculation, neurite outgrowth, and myelination. It interacts with receptors such as L1CAM, Caspr2, and other contactins to promote the formation of functional neural circuits. CNTN2 is also implicated in the organization of nodes of Ranvier, where it stabilizes interactions between axons and myelinating glial cells. Genetic studies have linked CNTN2 mutations to neurodevelopmental and neuropsychiatric disorders, including autism and epilepsy, where its dysregulation disrupts neural connectivity and excitability. It has also been studied in the context of autoimmune diseases like multiple sclerosis, where anti-CNTN2 antibodies contribute to neuroinflammation and demyelination. Structurally, CNTN2 shares immunoglobulin-like and fibronectin type III domains with other contactins, allowing it to mediate dynamic and specific cell-cell interactions in the nervous system.