Neural cell adhesion molecule (NCAM), also called CD56, is a homophilic binding glycoprotein expressed on the surface of neurons, glia, skeletal muscle and natural killer cells. NCAM has been implicated as having a role in cell–cell adhesion, neurite outgrowth, synaptic plasticity, and learning and memory. NCAM is thought to signal to induce neurite outgrowth via the fibroblast growth factor receptor (FGFR) and act upon the p59Fyn signaling pathway. During hematopoiesis, CD56 is the prototypic marker of NK cells, also present on subset of CD4+ T cells and CD8+ T cells.
