Blog
About

17
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Human Upf1 is a highly processive RNA helicase and translocase with RNP remodelling activities

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          RNA helicases are implicated in most cellular RNA-dependent events. In eukaryotes however, only few have been functionally characterized. Upf1 is a RNA helicase essential for nonsense-mediated mRNA decay (NMD). Here, using magnetic tweezers and bulk assays, we observe that human Upf1 is able to translocate slowly over long single-stranded nucleic acids with a processivity >10 kb. Upf1 efficiently translocates through double-stranded structures and protein-bound sequences, demonstrating that Upf1 is an efficient ribonucleoprotein complex remodeler. Our observation of processive unwinding by an eukaryotic RNA helicase reveals that Upf1, once recruited onto NMD mRNA targets, can scan the entire transcript to irreversibly remodel the mRNP, facilitating its degradation by the NMD machinery.

          Abstract

          Upf1 is a multifunctional helicase involved in various DNA- and RNA-related processes, including nonsense-mediated mRNA decay (NMD). Here the authors demonstrate that Upf1 is a highly processive ribonucleoprotein complex remodeler—a capability likely important for Upf1's NMD function.

          Related collections

          Most cited references 52

          • Record: found
          • Abstract: found
          • Article: not found

          Structure and mechanism of helicases and nucleic acid translocases.

          Helicases and translocases are a ubiquitous, highly diverse group of proteins that perform an extraordinary variety of functions in cells. Consequently, this review sets out to define a nomenclature for these enzymes based on current knowledge of sequence, structure, and mechanism. Using previous definitions of helicase families as a basis, we delineate six superfamilies of enzymes, with examples of crystal structures where available, and discuss these structures in the context of biochemical data to outline our present understanding of helicase and translocase activity. As a result, each superfamily is subdivided, where appropriate, on the basis of mechanistic understanding, which we hope will provide a framework for classification of new superfamily members as they are discovered and characterized.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            NMD: a multifaceted response to premature translational termination.

            Although most mRNA molecules derived from protein-coding genes are destined to be translated into functional polypeptides, some are eliminated by cellular quality control pathways that collectively perform the task of mRNA surveillance. In the nonsense-mediated decay (NMD) pathway premature translation termination promotes the recruitment of a set of factors that destabilize a targeted mRNA. The same factors also seem to have key roles in repressing the translation of the mRNA, dissociating its terminating ribosome and messenger ribonucleoproteins (mRNPs), promoting the degradation of its truncated polypeptide product and possibly even feeding back to the site of transcription to interfere with splicing of the primary transcript.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              RecBCD enzyme and the repair of double-stranded DNA breaks.

              The RecBCD enzyme of Escherichia coli is a helicase-nuclease that initiates the repair of double-stranded DNA breaks by homologous recombination. It also degrades linear double-stranded DNA, protecting the bacteria from phages and extraneous chromosomal DNA. The RecBCD enzyme is, however, regulated by a cis-acting DNA sequence known as Chi (crossover hotspot instigator) that activates its recombination-promoting functions. Interaction with Chi causes an attenuation of the RecBCD enzyme's vigorous nuclease activity, switches the polarity of the attenuated nuclease activity to the 5' strand, changes the operation of its motor subunits, and instructs the enzyme to begin loading the RecA protein onto the resultant Chi-containing single-stranded DNA. This enzyme is a prototypical example of a molecular machine: the protein architecture incorporates several autonomous functional domains that interact with each other to produce a complex, sequence-regulated, DNA-processing machine. In this review, we discuss the biochemical mechanism of the RecBCD enzyme with particular emphasis on new developments relating to the enzyme's structure and DNA translocation mechanism.
                Bookmark

                Author and article information

                Journal
                Nat Commun
                Nat Commun
                Nature Communications
                Nature Pub. Group
                2041-1723
                03 July 2015
                2015
                : 6
                Affiliations
                [1 ]Institut de Biologie de l'Ecole Normale Supérieure, CNRS UMR8197 , Paris 75230, France
                [2 ]Institut de Biologie de l'Ecole Normale Supérieure, INSERM U1024 , Paris 75230, France
                [3 ]Laboratoire de Physique Statistique, Ecole Normale Supérieure, Université Pierre et Marie Curie Paris, Université Paris Diderot , CNRS, 24 rue Lhomond, Paris 75005, France
                Author notes
                [*]

                These authors contributed equally to this work.

                [†]

                Present address: Physics Department, Faculty of Science, The M.S. University of Baroda, Vadodara 390002, Gujarat, India.

                Article
                ncomms8581
                10.1038/ncomms8581
                4506499
                26138914
                Copyright © 2015, Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.

                This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

                Categories
                Article

                Uncategorized

                Comments

                Comment on this article