Schematic N-glycosylation pathway representation characteristic of high and low passage LNCaP cells.

<p>The steps to elaborate the glycan structures corresponding to both LNCaP cells lines are represented in a simplified N-glycosylation pathway according to the mass spectral structural data as well as the transcription expression data. A main feature for this pathway is the lower levels of Type I glycans (light blue filled rectangles) compared to type II glycans (light orange filled rectangles) in both cell lines, implying that glycans characteristic of both cell lines are principally type II glycans. Where indicated, genes in the pathways are listed in parenthesis and located below their corresponding enzymes. For example, the enzyme b4GalT, associated with type II glycans, is mainly represented by expression of B4GALT1 and B4GALT3 genes among other genes. The main difference between low and high passage LNCaP cell lines is the increased expression of FucTH (FUTI) in high passage LNCaP cells as noted in both microarray data and mass spectra based model predicted enzyme levels. This is also translated in increases of H(II) and Le^y epitopes (indicated by the glycan structures within the dark orange border rectangles). The dashed arrows point to glycan structures that are absent or marginally present. Quantitative detail of the corresponding type I and type II glycan abundances for the structures in this figure are depicted in both <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002813#pcbi-1002813-g005" target="_blank">Figures 5</a> and <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002813#pcbi-1002813-g006" target="_blank">6</a>. Initial steps of glycan formation as well as sialylation processing are omitted for simplicity.