Neural cell adhesion molecule 1 (NCAM-1) is a single-pass type I membrane protein, it belongs to a family of membrane-bound glycoproteins that are involved in Ca2+ independent cell matrix and homophilic or heterophilic cell-cell interactions. NCAM-1 is synthesized as a 761 aa preproprecursor that contains a 19 aa signal sequence, a 722 aa GPI-linked mature region, and a 20 aa C-terminal prosegment. The molecule contains five C-2 type Ig-like domains and two fibronectin type-III domains. NCAM-1 is a cell adhesion molecule involved in neuron-neuron adhesion, neurite fasciculation, outgrowth of neurites, etc. Acting as a receptor for rabies virus, NCAM-1 in the adult brain shows a decline of sialylation relative to earlier developmental periods.