Identifying Polysialylated Proteins in HL-60 cell line: Expanding the Toolkit for the study of polysialic acid

Polysialic acid (polySia), a long homopolymer consisting of α2,8-linked sialic acid, is a cell surface protein modification with known functions in human neuronal and immune cells. Despite tight regulation of expression and its involvement in physiology and disease, polySia remains largely understudied. As polySia is known to promote metastasis and affects cell adhesion it is no surprise that increase polySia are found in a variety of cancers. Despite this, identity of many polysialylated proteins is still unknown. The anionic and reactive nature of polySia makes its study challenging, indicating the need for the development of an analytical toolkit to effectively understand its role in biological processes. The introduction of a biorthogonal handle and an improved ELISA were previously shown to allow the modification and quantification of polySia. PolySia was recently shown to be part of a receptor-ligand interaction between T-lymphocytes and Dendritic Cells, further emphasizing the need for the development of an analytical toolkit. With the introduction of new methods allowing the study and quantification of polySia as well as alteration of its expression or function, new proteins and cellular interactions involving polySia can be discovered and the results can be applied to a molecular or disease setting.