 E.g., in the opportunistic human pathogen Pseudomonas aeruginosa the sRNA ReaL translationally silences rpoS mRNA.RpoS proteolysis forms another level of the sigma factor’s regulation.Degradation occurs via ClpXP, a barrel-shaped protease composed of two six-subunit rings of the ATP-dependent ClpX chaperone that surround two seven-subunit rings of ClpP (Repoila "et al.