CsrA
CsrA, short for carbon storage regulator A, is a small, global RNA-binding protein found in many bacteria. It acts as a master regulator of post-transcriptional gene expression, influencing metabolism, motility, biofilm formation, and virulence. The protein is typically a homodimer of ~7 kDa subunits that recognizes RNA sequences containing GGA motifs, usually within the 5' untranslated region or near the start codon of target mRNAs. Binding of CsrA to these sites often blocks ribosome access to the mRNA, repressing translation, and can also alter mRNA stability. As a result, CsrA can both repress and, in some contexts, stabilize transcripts.
CsrA activity is tightly controlled by regulatory small RNAs, notably CsrB and CsrC in Escherichia coli and
Biological roles attributed to CsrA include coordination of carbon and glycogen metabolism, regulation of glucose uptake,