This is a family of global regulator proteins. This protein is a RNA-binding protein and a global regulator of carbohydrate metabolism genes facilitating mRNA decay [1]. In E. coli CsrA binds the CsrB RNA molecule to form the Csr regulatory system which has a strong negative regulatory effect on glycogen biosynthesis, glyconeogenesis and glycogen catabolism and a positive regulatory effect on glycolysis [1]. In other bacteria such as Erwinia caratovara RmsA has been shown to regulate the production of virulence determinants, such extracellular enzymes [2]. RmsA binds to RmsB regulatory RNA.

1: The RNA molecule CsrB binds to the global regulatory protein CsrA and antagonizes its activity in Escherichia coli. Liu MY, Gui G, Wei B, Preston JF 3rd, Oakford L, Yuksel U, Giedroc DP, Romeo T; J Biol Chem 1997;272:17502-17510. PMID:9211896

2: Identification of a global repressor gene, rsmA, of Erwinia carotovora subsp. carotovora that controls extracellular enzymes, N-(3-oxohexanoyl)-L-homoserine lactone, and pathogenicity in soft-rotting Erwinia spp. Cui Y, Chatterjee A, Liu Y, Dumenyo CK, Chatterjee AK; J Bacteriol 1995;177:5108-5115. PMID:7665490