PathwayStep359 PathwayStep357 PathwayStep358 PathwayStep355 PathwayStep356 PathwayStep354 Phosphorylated BRF1 (Ser92, Ser203) Binds 14-3-3 Phosphorylated BRF1 (Ser54, Ser92, Ser203) Binds 14-3-3 Butyrate Response Factor1 (BRF1) Binds AU-rich Element in 3' UTR of mRNA BRF1 Complex Recruits RNA Degradation Activities Phosphorylation of BRF1 by Protein Kinase B/Akt Phosphorylation of BRF1 by MK2 Destabilization of mRNA by Butyrate Response Factor 1 (BRF1) Authored: May, B, 2009-12-29 Butyrate Response Factor 1 (BRF1, ZFP36L1, not to be confused with transcription factor IIIB) binds AU-rich elements in the 3' region of mRNAs. After binding, BRF1 recruits exonucleases (XRN1 and the exosome) and decapping enzymes (DCP1a and DCP2) to hydrolyze the RNA. The ability of BRF1 to direct RNA degradation is controlled by phosphorylation of BRF1. Protein kinase B/AKT1 phosphorylates BRF1 at serines 92 and 203. Phosphorylated BRF1 can still bind RNA but is sequestered by binding 14-3-3 protein, preventing BRF1 from destabilizing RNA. BRF1 is also phosphorylated by MK2 at serines 54, 92, 203, and at an unknown site in the C-terminus. It is unknown if this particular phosphorylated form of BRF1 binds 14-3-3. Edited: May, B, 2009-12-29 Pubmed11719186 Pubmed12440953 Pubmed12704645 Pubmed15687258 Pubmed16391004 Reactome Database ID Release 43450385 Reactome, http://www.reactome.org ReactomeREACT_24915 Reviewed: Wilusz, J, 2010-06-29