Molecular insights into the interaction of PYM with the Mago-Y14 core of the exon junction complex
Fulvia Bono1, Judith Ebert, Leonie Unterholzner
1European Molecular Biology Laboratory, Heidelberg, Germany.
Abstract:
The exon junction complex (EJC) is deposited on mRNAs as a consequence of splicing and influences postsplicing mRNA metabolism. The Mago-Y14 heterodimer is a core component of the EJC. Recently, the protein PYM has been identified as an interacting partner of Mago-Y14. Here we show that PYM is a cytoplasmic RNA-binding protein that is excluded from the nucleus by Crm1. PYM interacts directly with Mago-Y14 by means of its N-terminal domain. The crystal structure of the Drosophila ternary complex at 1.9 A resolution reveals that PYM binds Mago and Y14 simultaneously, capping their heterodimerization interface at conserved surface residues. Formation of this ternary complex is also observed with the human proteins. Mago residues involved in the interaction with PYM have been implicated in nonsense-mediated mRNA decay (NMD). Consistently, human PYM is active in NMD tethering assays. Together, these data suggest a role for PYM in NMD.
Insights
The protein PYM interacts with the Mago-Y14 heterodimer, a core component of the exon junction complex (EJC). This interaction suggests a role for PYM in nonsense-mediated mRNA decay (NMD).
Area of Science:
- Molecular Biology
- RNA Metabolism
- Protein Interactions
Background:
- The exon junction complex (EJC) is crucial for mRNA processing and metabolism after splicing.
- The Mago-Y14 heterodimer is a key component of the EJC.
- PYM protein was recently identified as a Mago-Y14 interacting partner.
Purpose of the Study:
- To investigate the interaction between PYM and the Mago-Y14 heterodimer.
- To elucidate the structural basis of the PYM-Mago-Y14 complex.
- To determine the functional role of PYM in mRNA metabolism, specifically nonsense-mediated mRNA decay (NMD).
Main Methods:
- Biochemical assays to confirm PYM interaction with Mago-Y14.
- Crystal structure determination of the Drosophila ternary complex (PYM-Mago-Y14).
- Nonsense-mediated mRNA decay (NMD) tethering assays using human proteins.
Main Results:
- PYM is a cytoplasmic RNA-binding protein excluded from the nucleus by Crm1.
- PYM directly binds Mago-Y14 via its N-terminal domain.
- The crystal structure revealed PYM simultaneously binds Mago and Y14, capping their interface.
- The ternary complex formation is conserved in human proteins.
- PYM interaction sites on Mago are implicated in NMD.
- Human PYM demonstrated activity in NMD tethering assays.
Conclusions:
- PYM forms a ternary complex with the Mago-Y14 heterodimer.
- The structural data provides insights into the molecular mechanism of PYM binding.
- PYM plays a role in nonsense-mediated mRNA decay (NMD).
Related Concept Videos
02:32Exon Recombination
Exon shuffling follows “splice frame rules.” Each exon has three reading...
01:02Long-patch Base Excision Repair
01:08Nucleotide Excision Repair
01:38Nucleotide Excision Repair
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
01:08Nucleotide Excision Repair
00:55DNA Helicases