Probably a connector protein for RcsB/C regulation of biofilm formation, providing additional signal input into the two-component signaling pathway. Partially antagonizes the activities of YmgA and AriR, proteins that, via the Rcs phosphorelay, promote the synthesis of colanic acid, an exopolysaccharide and matrix component. Expressed constitutively at low levels, slightly induced upon entry into stationary phase at 37 degrees Celsius. Induced by 5-fluorouracil. Strongly induced at 16 and 23 degrees Celsius. Expression is partially dependent on RpoS, it is repressed by YcgE. At 16 degrees Celsius with blue light irradiation, expression of this operon is absolutely dependent on YcgF for relief from YcgE repression. Part of the ycgZ-ymgA-ariR-ymgC operon.