In the heart, multiple cell surface glycoproteins, including calcium, potassium and sodium ion channels, work in concert to propagate electrical impulses to generate proper action potentials and subsequent contraction of the myocardium. The appropriate abundance, distribution, and post-translational modifications of these glycoproteins are required for proper function. Specifically, the glycan-moiety attached to the protein is critical for proper protein folding, stability and signaling. For example, genetic defects that impact ion channel glycosylation sites result in impaired heart function.

Despite mounting evidence that glycan structures are key modulators of heart function and must be considered when developing cardiac biomarkers, we currently do not have a comprehensive view of the glycans present in the normal human heart. Ultimately, to understand the specific biological roles of glycoproteins, it is often necessary to define the population of each molecular species that arises from combinations of site-specific glycan diversity (i.e. microheterogeneity) at multiple sites of glycosylation, as this site-specific glycosylation may promote or interfere with interactions and signaling. Moreover, in a complex organ like the heart, cell type specificity is a critical piece of the puzzle, as the context and directionality of glycan-mediated events defines, for example, how cells propagate action potentials and multiple cell types interact during human development to properly form tissues.