Structural Aspects of Intermediate Filaments

  • Norbert Geisler
  • Klaus Weber

Abstract

Microtubules, microfilaments, and intermediate filaments (IF) form the three filamentous organizations of the cytoplasm. Whereas the major structural components of the two former systems—actin and tubulin—are highly conserved in different cell types, the constituent proteins of IF can vary greatly in amino acid sequence and length (40–200 K). This peculiar property led originally to much confusion as to the similarity and divergence of IF proteins. By the late 1970s it was obvious that IF proteins could be subdivided by biochemical and particularly by immunological data in a histologically meaningful manner as their expression pattern coincided with known rules of embryonic differentiation (for review see Lazarides, 1982; Osborn et al., 1982). Five subclasses were identified: epithelial keratins, neuronal neurofilaments, desmin filaments of most muscles, GFAP filaments of glia, and vimentin filaments present primarily in mesenchymal cells. Subsequent biochemical results documented around 20 different human keratins some of which were again markers of morphologically distinct epithelia (for review see Moll et al., 1982).

Keywords

Glycerol Urea Glycine Cysteine Proline 

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Copyright information

© Plenum Press, New York 1986

Authors and Affiliations

  • Norbert Geisler
    • 1
  • Klaus Weber
    • 1
  1. 1.Max Planck Institute for Biophysical ChemistryGoettingenFederal Republic of Germany

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