Figure 5
From: The space of enzyme regulation in HeLa cells can be inferred from its intracellular metabolome
Heterogeneity and co-regulation in HeLa cells.
(A) Comparison of the log-fold changes in enzyme activity by either gene expression analysis of 58 microarray samples (20 HaCaT/keratinocyte and 38 HeLa) or the EDAs obtained from metabolome data. Colors denote pathways and are the same as in Fig. 2 and panel B of this figure. Triangles denote enzymes that are significantly regulated in their EDAs and gene expression. (B) Standard deviations of HeLa/HaCaT log-fold changes as obtained after optimizations. Each point denotes a reaction and the colors are the same as used in Fig. 2. The blue-shaded area denotes a change in standard deviation from HaCaT to HeLa by a factor of 3. The blue line denotes a 1:1 relationship between standard deviations. (C) Correlation matrix for log-fold changes in differential heterogeneous reactions in HeLa cells, as obtained from the EDAs. Names denote enzymes and the type of regulation relative to HaCaT cells is denoted in brackets. (D) Illustration of the proposed major metabolic changes in HeLa cells. Proliferation in HeLa cells requires higher enzyme activities in glycolysis (mostly due to phosphofructokinase) and increased fidelity in the entry to the TCA cycle (red arrows). Additionally, higher activity in the TCA cycle and respiration lead to up-regulation of the pentose phosphate pathway which is drained into NADPH, nucleotide precursors and glycolytic intermediates (blue arrows).
