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Conserved segments 1A and 2B of the intermediate filament dimer: their atomic structures and role in filament

Sergei V Strelkov1, Harald Herrmann, Norbert Geisler

  • 1Maurice E.Müller Institute for Structural Biology, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland. sergei-v.strelkov@unibas.ch

The EMBO Journal
|March 13, 2002
PubMed

Insights

Intermediate filaments (IFs) are crucial cytoskeletal components. This study reveals the atomic-level structure of key IF segments, uncovering their roles in filament assembly and organization.

Area of Science:

  • Cell biology
  • Structural biology
  • Biochemistry

Background:

  • Intermediate filaments (IFs) are essential cytoskeletal elements in eukaryotic cells.
  • The basic unit of IFs is a coiled-coil dimer formed by alpha-helical segments.
  • Segments 1A and 2B are vital for IF assembly due to conserved sequences.

Purpose of the Study:

  • To elucidate the molecular organization of vimentin segments 1A and 2B at the atomic level.
  • To understand the role of these segments in intermediate filament assembly and structure.

Main Methods:

  • Crystal structure determination of human vimentin fragments (PDB: 1gk4, 1gk6, 1gk7) at high resolution (1.4-2.3 A).
  • Analysis of the structural features and potential interactions of segments 1A and 2B.

Main Results:

  • Segment 1A forms an amphipathic alpha-helix, potentially involved in dimer-dimer interactions.
  • Segment 2B forms a double-stranded coiled coil with a 'stutter' region near Phe351.
  • A C-terminal 2B fragment significantly disrupts IF assembly and alters filament structure.

Conclusions:

  • Provides the first atomic-level insights into intermediate filament architecture and function.
  • Highlights the distinct roles of segments 1A and 2B in IF assembly and higher-order structure formation.
  • Suggests potential mechanisms for IF assembly regulation through segment interactions.

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