7
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      New Model for Stacking Monomers in Filamentous Actin from Skeletal Muscles of Oryctolagus cuniculus

      research-article

      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

          To date, some scientific evidence (limited proteolysis, mass spectrometry analysis, electron microscopy (EM)) has accumulated, which indicates that the generally accepted model of double-stranded of filamentous actin (F-actin) organization in eukaryotic cells is not the only one. This entails an ambiguous understanding of many of the key cellular processes in which F-actin is involved. For a detailed understanding of the mechanism of F-actin assembly and actin interaction with its partners, it is necessary to take into account the polymorphism of the structural organization of F-actin at the molecular level. Using electron microscopy, limited proteolysis, mass spectrometry, X-ray diffraction, and structural modeling we demonstrated that F-actin presented in the EM images has no double-stranded organization, the regions of protease resistance are accessible for action of proteases in F-actin models. Based on all data, a new spatial model of filamentous actin is proposed, and the F-actin polymorphism is discussed.

          Related collections

          Most cited references63

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

          The interaction of Arp2/3 complex with actin: nucleation, high affinity pointed end capping, and formation of branching networks of filaments.

          The Arp2/3 complex is a stable assembly of seven protein subunits including two actin-related proteins (Arp2 and Arp3) and five novel proteins. Previous work showed that this complex binds to the sides of actin filaments and is concentrated at the leading edges of motile cells. Here, we show that Arp2/3 complex purified from Acanthamoeba caps the pointed ends of actin filaments with high affinity. Arp2/3 complex inhibits both monomer addition and dissociation at the pointed ends of actin filaments with apparent nanomolar affinity and increases the critical concentration for polymerization at the pointed end from 0.6 to 1.0 microM. The high affinity of Arp2/3 complex for pointed ends and its abundance in amoebae suggest that in vivo all actin filament pointed ends are capped by Arp2/3 complex. Arp2/3 complex also nucleates formation of actin filaments that elongate only from their barbed ends. From kinetic analysis, the nucleation mechanism appears to involve stabilization of polymerization intermediates (probably actin dimers). In electron micrographs of quick-frozen, deep-etched samples, we see Arp2/3 bound to sides and pointed ends of actin filaments and examples of Arp2/3 complex attaching pointed ends of filaments to sides of other filaments. In these cases, the angle of attachment is a remarkably constant 70 +/- 7 degrees. From these in vitro biochemical properties, we propose a model for how Arp2/3 complex controls the assembly of a branching network of actin filaments at the leading edge of motile cells.
            Bookmark
            • Record: found
            • Abstract: not found
            • Article: not found

            Cellular Motility Driven by Assembly and Disassembly of Actin Filaments

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

              Actin structure and function.

              Actin is the most abundant protein in most eukaryotic cells. It is highly conserved and participates in more protein-protein interactions than any known protein. These properties, along with its ability to transition between monomeric (G-actin) and filamentous (F-actin) states under the control of nucleotide hydrolysis, ions, and a large number of actin-binding proteins, make actin a critical player in many cellular functions, ranging from cell motility and the maintenance of cell shape and polarity to the regulation of transcription. Moreover, the interaction of filamentous actin with myosin forms the basis of muscle contraction. Owing to its central role in the cell, the actin cytoskeleton is also disrupted or taken over by numerous pathogens. Here we review structures of G-actin and F-actin and discuss some of the interactions that control the polymerization and disassembly of actin.
                Bookmark

                Author and article information

                Journal
                Int J Mol Sci
                Int J Mol Sci
                ijms
                International Journal of Molecular Sciences
                MDPI
                1422-0067
                06 November 2020
                November 2020
                : 21
                : 21
                : 8319
                Affiliations
                [1 ]Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia; quark777a@ 123456gmail.com (A.V.G.); alan@ 123456vega.protres.ru (A.K.S.); syugrishin@ 123456gmail.com (S.Y.G.); seliv@ 123456vega.protres.ru (O.M.S.); marrruko@ 123456yandex.ru (M.Y.S.)
                [2 ]Institute of Mathematical Problems of Biology, Russian Academy of Sciences, Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
                [3 ]The Branch of the Institute of Bioorganic Chemistry, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
                [4 ]State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Moscow Region, Russia
                [5 ]Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia; liamar@ 123456rambler.ru (L.G.B.); ivanvikhlyantsev@ 123456gmail.com (I.M.V.)
                Author notes
                [* ]Correspondence: ogalzit@ 123456vega.protres.ru ; Tel.: +7-903-675-0156
                Author information
                https://orcid.org/0000-0001-7373-9808
                https://orcid.org/0000-0001-6063-6789
                https://orcid.org/0000-0002-3962-1520
                Article
                ijms-21-08319
                10.3390/ijms21218319
                7664232
                33171915
                9f8673fb-e1cc-4fc9-a42e-03cd97b2a603
                © 2020 by the authors.

                Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( http://creativecommons.org/licenses/by/4.0/).

                History
                : 29 September 2020
                : 03 November 2020
                Categories
                Article

                Molecular biology
                actin,monomer,filament,proteolysis,accessible surface area,mass spectrometry,electron microscopy

                Comments

                Comment on this article