description
AUF1 (hnRNP D0) dimers bind U-rich regions of AU-rich elements (AREs) in the 3' untranslated regions of mRNAs. The binding causes AUF1 dimers to assemble into higher order tetrameric complexes. Diphosphorylated AUF1 bound to RNA recruits additional proteins, including eIF4G, polyA-binding protein, Hsp, Hsc70, Hsp27, NSEP-1, NSAP-1, and IMP-2 which target the mRNA and AUF1 for degradation. Unphosphorylated AUF1 is thought to be less able to recruit additional proteins. AUF1 also interacts directly or indirectly with HuR and the RNA-induced silencing complex (RISC).AUF1 complexed with RNA and other proteins is ubiquitinated and targeted for destruction by the proteasome while the bound mRNA is degraded. Inhibition of ubiquitin addition to AUF1 blocks mRNA degradation. The mechanism by which ubiquitin-dependent proteolysis is coupled to mRNA degradation is unknown.At least 4 isoforms of AUF1 exist: p45 (45 kDa) contains all exons, p42 lacks exon 2, p40 lacks exon 7, and p37 lacks exons 2 and 7. The presence of exon 7 in p42 and p45 seems to block ubiquitination while the absence of exon 7 (p37 and p40) targets AUF1 for ubiquitination and destabilizes bound RNAs. Lack of exon 2 (p37 and p42) is associated with higher affinity for RNA and 14-3-3sigma (SFN).AUF1 binds and destabilizes mRNAs encoding Interleukin-1 beta (IL1B), Tumor Necrosis Factor alpha (TNFA), Cyclin-dependent kinase inhibitor 1 (CDNK1A, p21), Cyclin-D1 (CCND1), Granulocyte-macrophage colony stimulating factor (GM-CSF, CSF2), inducible Nitric oxide synthase (iNOS, NOS2), Proto-oncogene cFos (FOS), Myc proto-oncogene (MYC), Apoptosis regulator Bcl-2 (BCL2)

external resources
NCBI:1269726
REACTOME:R-HSA-450408
PUBMED:16391004
PUBMED:12704645
PUBMED:10205060
PUBMED:12440953
PUBMED:18573886
PUBMED:12819195

genes
EIF4G1 , HNRNPD , HSPA1A , HSPA8 , HSPB1 , PSMA1 , PSMA2 , PSMA3 , PSMA4 , PSMA5 , PSMA6 , PSMA7 , PSMB1 , PSMB2 , PSMB3 , PSMB4 , PSMB5 , PSMB6 , PSMB7 , PSMB8 , PSMB9 , PSMB10 , PSMC1 , PSMC2 , PSMC3 , PSMC4 , PSMC5 , PSMC6 , PSMD1 , PSMD2 , PSMD3 , PSMD4 , PSMD5 , PSMD7 , PSMD8 , PSMD9 , PSMD10 , PSMD11 , PSMD12 , PSMD13 , PSME1 , PSME2 , RPS27A , UBA52 , UBB , UBC , SEM1 , PSMF1 , PSMD6 , PSME3 , PSMD14 , PSME4 , PABPC1 , PSMB11 , PSMA8 , C7orf76 , LOC100506136 ,