Structural requirements for the assembly of LINC complexes and their function in cellular mechanical stiffness

Exp Cell Res. 2008 May 1;314(8):1892-905. doi: 10.1016/j.yexcr.2008.02.022. Epub 2008 Mar 12.

Abstract

The evolutionary-conserved interactions between KASH and SUN domain-containing proteins within the perinuclear space establish physical connections, called LINC complexes, between the nucleus and the cytoskeleton. Here, we show that the KASH domains of Nesprins 1, 2 and 3 interact promiscuously with luminal domains of Sun1 and Sun2. These constructs disrupt endogenous LINC complexes as indicated by the displacement of endogenous Nesprins from the nuclear envelope. We also provide evidence that KASH domains most probably fit a pocket provided by SUN domains and that post-translational modifications are dispensable for that interaction. We demonstrate that the disruption of endogenous LINC complexes affect cellular mechanical stiffness to an extent that compares to the loss of mechanical stiffness previously reported in embryonic fibroblasts derived from mouse lacking A-type lamins, a mouse model of muscular dystrophies and cardiomyopathies. These findings support a model whereby physical connections between the nucleus and the cytoskeleton are mediated by interactions between diverse combinations of Sun proteins and Nesprins through their respective evolutionary-conserved domains. Furthermore, they emphasize, for the first time, the relevance of LINC complexes in cellular mechanical stiffness suggesting a possible involvement of their disruption in various laminopathies, a group of human diseases linked to mutations of A-type lamins.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Biomechanical Phenomena
  • Cell Line
  • Cytoskeletal Proteins
  • Cytoskeleton / physiology
  • Humans
  • Intracellular Signaling Peptides and Proteins / chemistry*
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Membrane Proteins / chemistry*
  • Membrane Proteins / metabolism
  • Mice
  • Microfilament Proteins / chemistry*
  • Microfilament Proteins / metabolism
  • Microtubule-Associated Proteins / chemistry*
  • Microtubule-Associated Proteins / metabolism
  • Molecular Sequence Data
  • Nerve Tissue Proteins / chemistry*
  • Nerve Tissue Proteins / metabolism
  • Nuclear Lamina / chemistry
  • Nuclear Lamina / physiology
  • Nuclear Proteins / chemistry*
  • Nuclear Proteins / metabolism
  • Protein Structure, Tertiary

Substances

  • Cytoskeletal Proteins
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • Microfilament Proteins
  • Microtubule-Associated Proteins
  • Nerve Tissue Proteins
  • Nuclear Proteins
  • SUN1 protein, human
  • SUN2 protein, human
  • SYNE1 protein, human
  • SYNE2 protein, human
  • nesprin 3 protein, human