{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nThe ribosome-associated protein PYM plays a central role in post-splicing mRNA regulation by disassembling fully assembled exon junction complexes (EJCs) from spliced mRNAs. It binds directly to the core EJC proteins MAGOH and Y14, thereby facilitating their removal and recycling during translation. Disruption of this disassembly process—either by PYM overexpression or depletion—leads to impaired recycling of EJC components and alters mRNA surveillance pathways, such as nonsense-mediated decay."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n \nIn addition to its disassembly function, PYM acts as a molecular bridge that connects EJC-bearing spliced mRNAs to the translation machinery. It employs distinct binding domains to interact both with the Y14–MAGOH complex in the cytoplasm and with the 40S ribosomal subunit, as well as the 48S preinitiation complex. This dual engagement enhances the translation efficiency of mRNAs produced from intron-containing pre-mRNAs—a benefit not observed with intronless transcripts."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": "\n\nTogether, these studies define PYM as a multifunctional regulator that coordinates the removal of EJCs with the initiation of translation. By ensuring that spliced mRNAs are both properly demasked and efficiently channeled into the translation machinery, PYM provides a critical mechanistic link between RNA processing and protein synthesis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Niels H Gehring, Styliani Lamprinaki, Andreas E Kulozik, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Disassembly of exon junction complexes by PYM."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Cell (2009)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.cell.2009.02.042"}], "href": "https://doi.org/10.1016/j.cell.2009.02.042"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19410547"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19410547"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Michael D Diem, Chia C Chan, Ihab Younis, et al. "}, {"type": "b", "children": [{"type": "t", "text": "PYM binds the cytoplasmic exon-junction complex and ribosomes to enhance translation of spliced mRNAs."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Nat Struct Mol Biol (2007)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/nsmb1321"}], "href": "https://doi.org/10.1038/nsmb1321"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "18026120"}], "href": "https://pubmed.ncbi.nlm.nih.gov/18026120"}]}]}]}