B Increasing protein age results in increasing tandem reporter ratio. The fluorophore states of the tFT reporter are shown in the inset: (1) immature; (2) only sfGFP matured; (3) only intermediate mCherry matured; (4) sfGFP and intermediate mCherry matured; (5) only mCherry matured; and (6) both mCherry and sfGFP matured. kg, kr1, kr2 denote the maturation rates of sfGFP, intermediate mCherry and fully-matured mCherry respectively. The different curves correspond to sets of values for kg, kr1, kr2 selected from Gaussian distributions with half-time means 27, 40 and 9 minutes and standard deviations 2.7, 4 and 0.9 minutes respectively. 