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Complexes between the nonsense-mediated mRNA decay pathway factor human upf1 (up-frameshift protein 1) and essential

Thomas Schell1, Thomas Köcher, Matthias Wilm

  • 1European Molecular Biology Laboratory Heidelberg, Gene Expression Programme, Meyerhofstrasse 1, 69117 Heidelberg, Germany.

The Biochemical Journal
|May 2, 2003
PubMed

Insights

Researchers identified new protein interactions involved in nonsense-mediated mRNA decay (NMD). Human up-frameshift protein 1 (Hupf1) interacts with Hupf2, Hupf3a/b, and poly(A)-binding protein, revealing new insights into mRNA quality control.

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • Nonsense-mediated mRNA decay (NMD) is a crucial cellular surveillance pathway that degrades aberrant mRNAs containing premature translation-termination codons.
  • Human up-frameshift protein 1 (Hupf1) is a conserved protein essential for NMD function in mammals and yeast.

Purpose of the Study:

  • To identify cellular proteins that interact with Hupf1.
  • To elucidate the role of these interacting proteins in the NMD pathway.

Main Methods:

  • Generation of a stable HeLa cell line expressing a double-affinity tagged Hupf1 (Hupf1-2tag).
  • Affinity chromatography to isolate Hupf1-2tag-associated protein complexes.
  • Mass spectrometry (MS) and immunoblotting for protein identification.
  • Size-exclusion chromatography to assess complex formation.

Main Results:

  • Hupf1 was found to interact with known NMD factors Hupf2 and Hupf3a/b.
  • Evidence suggests Hupf1, Hupf2, and Hupf3a may form a large, stable complex (~1.3 MDa).
  • Poly(A)-binding protein was identified as a Hupf1 interactor, with its association sensitive to RNase treatment, suggesting an RNA-dependent interaction.

Conclusions:

  • The study identifies novel interaction partners of Hupf1 within the NMD pathway.
  • The findings suggest a potential multi-protein complex involving Hupf1, Hupf2, and Hupf3a.
  • The interaction with poly(A)-binding protein highlights a potential link between mRNA polyadenylation status and NMD regulation.

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