Abstract

Isoforms of the neuronal cell adhesion molecule (NCAM) carrying the linear homopolymer of alpha 2,8-linked sialic acid (polysialic acid, PSA) have emerged as particularly attractive candidates for promoting plasticity in the nervous system. The large negatively charged PSA chain of NCAM is considered as a spacer that reduces adhesion forces between cells allowing dynamic changes in membrane contacts. However, accumulating evidence also suggest that PSA-NCAM mediated interactions lead to activation of intracellular signaling cascades that are fundamental to the biological functions of the molecule. An important role of PSA-NCAM appears to be during development, when its expression level is high and where it contributes to regulate transformations of cell shape, cell growth or cell migration. However, PSA-NCAM does persist in adult brain structures that display a high degree of plasticity as the hippocampus where it is involved in activity- induced synaptic plasticity. In this review, we will discuss the recent findings on the structure, synthesis and signaling activity of PSA-NCAM essential to understand its role in synaptic plasticity.

Keywords: Glutamate Receptors, mitogen-activated protein (MAP) kinase pathway, FGF Receptor, Neurotrophin, long-term depression