Cluster analysis of differentially expressed proteins and categorization by protein functions.

<p>(A) Differentially expressed proteins were clustered into six different categories with Groups 1–3 representing down-regulated proteins while Groups 4–6 representing upregulated proteins. In Group 1, 39 proteins decreased significantly at all four culture time points (1, 3, 5 and 7 days). In Group 2, 31 proteins were downregulated after 3 days of co-culture. In Group 3, the expression levels of 22 proteins decreased after 5 days of co-culture. In Group 4, 14 proteins showed gradual increase in expression during the 7 day course of co-culture. In Group 5, 18 proteins significantly increased in their expression on day 7. For Group 6, 13 proteins had increased expression by day 3. All categorized proteins were then evaluated for their functional annotations according to the PANTHER and BlastGO classification systems. Proteins were further enriched in a variety of cellular functions and their functionality is briefly summarized. Arrowheads indicate major cellular functions in Groups with upregulated expression patterns compared with Groups with downregulated patterns. (B) Schematic representation of potential functions of differentially expressed proteins throughout the culture period.