Arsenic-induced signaling and regulatory mechanisms involve transcriptional activators and the proteasome. (a-d) Significant network neighborhoods (p < 0.005) uncovered by the ActiveModules algorithm, with the search performed at depth 1 (all nodes in the network are the nearest neighbors of one central node): (a) FHL1 center; (b) PRE1 center and proteasome complex; (c) YAP1 and CAD1 centers; (d) HSF1 center. (e) An additional network centered on MET31 with functional relevance to the arsenic response, which, however, did not reach significance in this analysis, p < 0.11. (f) An overview of the network relationships between major arsenic-responsive transcription factors. Shades of red, induced; shades of green, repressed; blue boxed outline, significant expression; orange arrows, protein-DNA interaction; blue dashed lines, protein-protein interactions. The 2 h, 100 μM AsIII condition was used for the visual mappings. Many of the genes mapped to the network neighborhoods and displayed in this figure are boxed for the sake of clarity and space, but are mostly significantly differentially expressed.