Polysialic acid (polySia)

Polysialic acid is a linear homopolymer of sialic acid residues, commonly composed of α2,8-linked or α2,9-linked N-acetylneuraminic acid units[1][3]. It is primarily known as a post-translational modification of the neural cell adhesion molecule (NCAM) in vertebrates, dramatically altering cell–cell interactions due to its large size and strong negative charge[1][4][8]. Polysialic acid has a prominent role in neural development, cell migration, synapse formation, axon guidance, and the modulation of immune cell functions. Its biological effects are driven by its anti-adhesive, hydration, and charge-shielding properties. In cancer, polySia is linked to enhanced metastatic potential, and in certain pathogenic bacteria (such as Neisseria meningitidis), it forms the bacterial capsule, facilitating immune evasion[3][9]. Polysialic acid is not itself a druggable target, enzyme, receptor, or transporter but is a unique, regulated glycan modification on specific proteins, most notably NCAM.

Other names

PolySiapolysialicpoly-sialic acid