Meta-Biol

• Pathways

Tristetraproline (TTP) binds RNAs that contain AU-rich elements and recruits enzymes that degrade RNA. TTP interacts with the exosome (3' to 5' exonuclease), XRN1 (5' to 3' exonuclease), and the decapping enzymes DCP1 and DCP2a.
The activity of TTP is regulated by phosphorylation. MK2 phosphorylates TTP, which then binds 14-3-3.The interaction with 14-3-3 prevents phosphorylated TTP from entering stress granules and stabilizes mRNA bound by phosphorylated TTP. Tristetraproline is known to bind AU-rich elements in the following mRNAs: Tumor necrosis factor alpha (TNFA), Granulocyte-macrophage colony stimulating factor (CSF2, GM-CSF), Interleukin-2 (IL-2), and Proto-oncogene C-FOS (FOS, c-fos). Mice deficient in TTP exhibit arthritis, weight loss, skin lesions, autoimmunity, and myeloid hyperplasia.

RNA elements rich in adenine and uracil residues (AU-rich elements) bind specific proteins which either target the RNA for degradation or, more rarely, stabilize the RNA. The activity of the AU-element binding proteins is regulated, usually by phosphorylation but also by subcellular localization.

This superpathway encompasses the processes by which RNA transcription products are further modified covalently and non-covalently to yield their mature forms, and the regulation of these processes. Annotated pathways include ones for capping, splicing, and 3'-cleavage and polyadenylation to yield mature mRNA molecules that are exported from the nucleus (Hocine et al. 2010). mRNA editing and nonsense-mediated decay are also annotated. Processes leading to mRNA breakdown are described: deadenylation-dependent mRNA decay, microRNA-mediated RNA cleavage, and regulation of mRNA stability by proteins that bind AU-rich elements.psnRNP assembly is also annotated here.

The aminoacylation of mature tRNAs is annotated in the "Metabolism of proteins" superpathway, as a part of "Translation".