During the post-exponential growth phase transiently interferes with RpoS (sigma S) activity without affecting expression of RpoS itself. It is probably not an anti-sigma factor as its overexpression is detrimental in rapidly growing cells where there is almost no sigma S factor. There is a strong overlap between Crl-activated genes and FliZ-down-regulated genes. FliZ acts as a timing device for expression of the genes for the adhesive curli fimbriae by indirectly decreasing expression of the curli regulator CsgD. Induced in early post-exponential phase, its expression decreases again at OD578 2-2.5. Not required for motility, disruption leads to derepression of the adhesive curli fimbriae genes. Extended N-terminus.