2mfc

Structural highlights

Function

CSRA1_PSEPH A translational regulator that binds mRNA to regulate translation initiation and/or mRNA stability (PubMed:17704818, PubMed:23635605). Post-transcriptionally represses the expression of genes controlled by GacA/GacS (PubMed:15601712, PubMed:23635605). Binds the 5' UTR of mRNA; the mRNA binds to the outside edge to each monomer and each dimer could bind the same mRNA twice (PubMed:17704818). Recognizes a (A/U)CANGGANG(U/A) consensus, binds to GGA (part of the Shine-Dalgarno sequence) in the 5' UTR loop, which prevents ribosome binding (PubMed:17704818, PubMed:24561806, PubMed:23635605). Overexpression represses target protein expression; mutating nucleotides in the 5' UTR abolishes repression in vivo (PubMed:17704818, PubMed:23635605). Binds specifically to small RNAs (sRNA) RsmX, RsmZ and RsmY; these sRNAs fold into secondary structures with multiple GGA sequences in loops to which the CsrA proteins bind (PubMed:15601712, PubMed:16286659, PubMed:24828038). Binding to RsmX, RsmY or RsmZ titrates the protein so that it can no longer bind mRNA and repress translation (PubMed:15601712, PubMed:24828038). RsmZ can bind up to 5 CsrA1 (rsmE) dimers; they bind cooperatively to GGA sequences in RsmZ in a defined order (PubMed:24828038, PubMed:24561806). Required for optimal expression and stability of sRNAs RsmX, RsmY and RsmZ (PubMed:15601712, PubMed:16286659). Four CsrA1 dimers maximally protect RsmZ from RNase activity (PubMed:24828038). Deletion of rsmX, rsmY or rsmZ alone has no detectable phenotype, but a double rsmY-rsmZ deletion has a marked decrease in production of secondary metabolites HCN, exoprotease AprA, antifungal agent 2,4-diacetylphloroglucinol and swarming motility, and protects cucumber plants from fungal infection less well than wild-type; the triple sRNA deletion has even stronger loss of these phenotypes (PubMed:16286659).^{[1] [2] [3] [4] [5] [6]}

References

1. ↑ Reimmann C, Valverde C, Kay E, Haas D. Posttranscriptional repression of GacS/GacA-controlled genes by the RNA-binding protein RsmE acting together with RsmA in the biocontrol strain Pseudomonas fluorescens CHA0. J Bacteriol. 2005 Jan;187(1):276-85. PMID:15601712 doi:10.1128/JB.187.1.276-285.2005
2. ↑ Kay E, Dubuis C, Haas D. Three small RNAs jointly ensure secondary metabolism and biocontrol in Pseudomonas fluorescens CHA0. Proc Natl Acad Sci U S A. 2005 Nov 22;102(47):17136-41. PMID:16286659 doi:10.1073/pnas.0505673102
3. ↑ Schubert M, Lapouge K, Duss O, Oberstrass FC, Jelesarov I, Haas D, Allain FH. Molecular basis of messenger RNA recognition by the specific bacterial repressing clamp RsmA/CsrA. Nat Struct Mol Biol. 2007 Sep;14(9):807-13. Epub 2007 Aug 19. PMID:17704818 doi:10.1038/nsmb1285
4. ↑ Lapouge K, Perozzo R, Iwaszkiewicz J, Bertelli C, Zoete V, Michielin O, Scapozza L, Haas D. RNA pentaloop structures as effective targets of regulators belonging to the RsmA/CsrA protein family. RNA Biol. 2013 Jun;10(6):1031-41. PMID:23635605 doi:10.4161/rna.24771
5. ↑ Duss O, Michel E, Diarra Dit Konte N, Schubert M, Allain FH. Molecular basis for the wide range of affinity found in Csr/Rsm protein-RNA recognition. Nucleic Acids Res. 2014 Feb 21. PMID:24561806 doi:http://dx.doi.org/10.1093/nar/gku141
6. ↑ Duss O, Michel E, Yulikov M, Schubert M, Jeschke G, Allain FH. Structural basis of the non-coding RNA RsmZ acting as a protein sponge. Nature. 2014 May 29;509(7502):588-92. doi: 10.1038/nature13271. Epub 2014 May 14. PMID:24828038 doi:http://dx.doi.org/10.1038/nature13271