FIG 7.

Schematic representation of hypothetical iron- and PKA-dependent regulation of riboflavin synthesis. For four situations, high/low iron and high/low PKA activity, the hypothetical regulation of riboflavin synthesis is illustrated based on data from the manuscript as well as Chen et al. (32). Details can be found in the text. The higher the intensity/darkness of the depicted symbol or arrow, the higher the activity of the enzyme or reaction. Full arrows depict known interactions, striped arrows depict hypothetical, partially verified interactions, and dotted arrows depict purely hypothetical interactions. P, phosphate; PKA, protein kinase A.