YmgB is part of the three gene cluster ymgABC which has a role in biofilm development and stability. YmgB represses biofilm formation in rich medium containing glucose, decreases cellular motility and also protects the cell from acid which indicates that YmgB has an important function in acid-resistance [1]. YmgB binds as a dimer to genes which are important for biofilm formation via a ligand. Due to its important function in acid resistance it is also known as AriR (regulator of acid resistance influenced by indole) [1].

1: Structure and function of the Escherichia coli protein YmgB: a protein critical for biofilm formation and acid-resistance. Lee J, Page R, Garcia-Contreras R, Palermino JM, Zhang XS, Doshi O, Wood TK, Peti W; J Mol Biol. 2007;373:11-26. PMID:17765265