1. Biochemistry and Chemical Biology
  2. Structural Biology and Molecular Biophysics
Download icon

La-related protein 1 (LARP1) binds the mRNA cap, blocking eIF4F assembly on TOP mRNAs

  1. Roni M Lahr
  2. Bruno D Fonseca
  3. Gabrielle E Ciotti
  4. Hiba A Al-Ashtal
  5. Jian-Jun Jia
  6. Marius R Niklaus
  7. Sarah P Blagden
  8. Tommy Allain
  9. Andrea J Berman  Is a corresponding author
  1. University of Pittsburgh, United States
  2. Children's Hospital of Eastern Ontario Research Institute, Canada
  3. University of Oxford, United Kingdom
Research Article
  • Cited 69
  • Views 5,202
  • Annotations
Cite this article as: eLife 2017;6:e24146 doi: 10.7554/eLife.24146

Abstract

The 5’terminal oligopyrimidine (5’TOP) motif is a cis-regulatory RNA element located immediately downstream of the 7-methyl-guanosine [m7G] cap of TOP mRNAs, which encode ribosomal proteins and translation factors. In eukaryotes, this motif coordinates the synchronous and stoichiometric expression of the protein components of the translation machinery. La-related protein 1 (LARP1) binds TOP mRNAs, regulating their stability and translation. We present crystal structures of the human LARP1 DM15 region in complex with a 5’TOP motif, a cap analog (m7GTP), and a capped cytosine (m7GpppC) resolved to 2.6, 1.8 and 1.7 Å, respectively. Our binding, competition, and immunoprecipitation data corroborate and elaborate on the mechanism of 5’TOP motif binding by LARP1. We show that LARP1 directly binds the cap and adjacent 5’TOP motif of TOP mRNAs, effectively impeding access of eIF4E to the cap and preventing eIF4F assembly. Thus, LARP1 is a specialized TOP mRNA cap-binding protein that controls ribosome biogenesis.

Data availability

The following data sets were generated
    1. Lahr and Berman
    (2017) DM15-RNA cocrystal
    Publicly available at the RCSB Protein Data Bank (accession no: 5V7C).
    1. Lahr and Berman
    (2017) DM15-m7GTP cocrystal
    Publicly available at the RCSB Protein Data Bank (accession no: 5V4R).
    1. Lahr and Berman
    (2017) DM15-m7GpppC cocrystal
    Publicly available at the RCSB Protein Data Bank (accession no: 5V87).

Article and author information

Author details

  1. Roni M Lahr

    Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Bruno D Fonseca

    Children's Hospital of Eastern Ontario Research Institute, Ottawa, Canada
    Competing interests
    The authors declare that no competing interests exist.
  3. Gabrielle E Ciotti

    Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Hiba A Al-Ashtal

    Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Jian-Jun Jia

    Children's Hospital of Eastern Ontario Research Institute, Ottawa, Canada
    Competing interests
    The authors declare that no competing interests exist.
  6. Marius R Niklaus

    Children's Hospital of Eastern Ontario Research Institute, Ottawa, Canada
    Competing interests
    The authors declare that no competing interests exist.
  7. Sarah P Blagden

    Department of Oncology, University of Oxford, Oxford, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  8. Tommy Allain

    Children's Hospital of Eastern Ontario Research Institute, Ottawa, Canada
    Competing interests
    The authors declare that no competing interests exist.
  9. Andrea J Berman

    Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
    For correspondence
    ajb190@pitt.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-1217-7412

Funding

National Institute of General Medical Sciences (R01GM116889)

  • Andrea J Berman

Prostate Cancer Canada (PCC Discovery Grant D2015-02)

  • Bruno D Fonseca
  • Tommy Allain

University of Pittsburgh

  • Roni M Lahr
  • Gabrielle E Ciotti
  • Hiba A Al-Ashtal
  • Andrea J Berman

Samuel and Emma Winters Foundation

  • Andrea J Berman

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Cynthia Wolberger, Johns Hopkins University, United States

Publication history

  1. Received: December 11, 2016
  2. Accepted: April 4, 2017
  3. Accepted Manuscript published: April 5, 2017 (version 1)
  4. Accepted Manuscript updated: April 7, 2017 (version 2)
  5. Version of Record published: May 5, 2017 (version 3)

Copyright

© 2017, Lahr et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 5,202
    Page views
  • 1,093
    Downloads
  • 69
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

Further reading

    1. Biochemistry and Chemical Biology
    2. Structural Biology and Molecular Biophysics
    Quentin M Smith et al.
    Research Article

    Regulated thin filaments (RTFs) tightly control striated muscle contraction through calcium binding to troponin, which enables tropomyosin to expose myosin-binding sites on actin. Myosin binding holds tropomyosin in an open position, exposing more myosin-binding sites on actin, leading to cooperative activation. At lower calcium levels, troponin and tropomyosin turn off the thin filament; however, this is antagonised by the high local concentration of myosin, questioning how the thin filament relaxes. To provide molecular details of deactivation, we used single-molecule imaging of green fluorescent protein (GFP)-tagged myosin-S1 (S1-GFP) to follow the activation of RTF tightropes. In sub-maximal activation conditions, RTFs are not fully active, enabling direct observation of deactivation in real time. We observed that myosin binding occurs in a stochastic step-wise fashion; however, an unexpectedly large probability of multiple contemporaneous detachments is observed. This suggests that deactivation of the thin filament is a coordinated active process.

    1. Biochemistry and Chemical Biology
    Maria Carmela Filomena et al.
    Research Article

    Myopalladin (MYPN) is a striated muscle-specific immunoglobulin domain-containing protein located in the sarcomeric Z-line and I-band. MYPN gene mutations are causative for dilated (DCM), hypertrophic and restrictive cardiomyopathy. In a yeast two-hybrid screening, MYPN was found to bind to titin in the Z-line, which was confirmed by microscale thermophoresis. Cardiac analyses of MYPN knockout (MKO) mice showed the development of mild cardiac dilation and systolic dysfunction, associated with decreased myofibrillar isometric tension generation and increased resting tension at longer sarcomere lengths. MKO mice exhibited a normal hypertrophic response to transaortic constriction (TAC), but rapidly developed severe cardiac dilation and systolic dysfunction, associated with fibrosis, increased fetal gene expression, higher intercalated disc fold amplitude, decreased calsequestrin-2 protein levels, and increased desmoplakin and SORBS2 protein levels. Cardiomyocyte analyses showed delayed Ca2+ release and reuptake in unstressed MKO mice as well as reduced Ca2+ spark amplitude post-TAC, suggesting that altered Ca2+ handling may contribute to the development of DCM in MKO mice.