Desmin filaments influence myofilament spacing and lateral compliance of slow skeletal muscle fibres.

Research output: Contribution to journalArticle

Abstract

Intermediate filaments composed of desmin interlink Z-disks and sarcolemma in skeletal muscle. Depletion of desmin results in lower active stress of smooth, cardiac, and skeletal muscles. Structural functions of intermediate filaments in fast (psoas) and slow (soleus) skeletal muscle were examined using x-ray diffraction on permeabilized muscle from desmin-deficient mice (Des–/–) and controls (Des+/+). To examine lateral compliance of sarcomeres and cells, filament distances and fiber width were measured during osmotic compression with dextran. Equatorial spacing (x-ray diffraction) of contractile filaments was wider in soleus Des–/– muscle compared to Des+/+, showing that desmin is important for maintaining lattice structure. Osmotic lattice compression was similar in Des–/– and Des+/+. In width measurements of single fibers and bundles, Des–/– soleus were more compressed by dextran compared to Des+/+, showing that intermediate filaments contribute to whole-cell compliance. For psoas fibers, both filament distance and cell compliance were similar in Des–/– and Des+/+. We conclude that desmin is important for stabilizing sarcomeres and maintaining cell compliance in slow skeletal muscle. Wider filament spacing in Des–/– soleus cannot, however, explain the lower active stress, but might influence resistance to stretch, possibly minimizing stretch-induced cell injury.

Details

Authors
  • Johanna Balogh
  • Anders Arner
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biophysics
Original languageEnglish
Pages (from-to)1156-1165
JournalBiophysical Journal
Volume88
Issue number2
Publication statusPublished - 2005
Publication categoryResearch
Peer-reviewedYes