Collagen remodeling by phagocytosis is determined by collagen substrate topology and calcium-dependent interactions of gelsolin with nonmuscle myosin IIA in cell adhesions

Mol Biol Cell. 2013 Mar;24(6):734-47. doi: 10.1091/mbc.E12-10-0754. Epub 2013 Jan 16.

Abstract

We examine how collagen substrate topography, free intracellular calcium ion concentration ([Ca(2+)]i, and the association of gelsolin with nonmuscle myosin IIA (NMMIIA) at collagen adhesions are regulated to enable collagen phagocytosis. Fibroblasts plated on planar, collagen-coated substrates show minimal increase of [Ca(2+)]i, minimal colocalization of gelsolin and NMMIIA in focal adhesions, and minimal intracellular collagen degradation. In fibroblasts plated on collagen-coated latex beads there are large increases of [Ca(2+)]i, time- and Ca(2+)-dependent enrichment of NMMIIA and gelsolin at collagen adhesions, and abundant intracellular collagen degradation. NMMIIA knockdown retards gelsolin recruitment to adhesions and blocks collagen phagocytosis. Gelsolin exhibits tight, Ca(2+)-dependent binding to full-length NMMIIA. Gelsolin domains G4-G6 selectively require Ca(2+) to interact with NMMIIA, which is restricted to residues 1339-1899 of NMMIIA. We conclude that cell adhesion to collagen presented on beads activates Ca(2+) entry and promotes the formation of phagosomes enriched with NMMIIA and gelsolin. The Ca(2+) -dependent interaction of gelsolin and NMMIIA in turn enables actin remodeling and enhances collagen degradation by phagocytosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Calcium / metabolism*
  • Cell Adhesion
  • Cells, Cultured
  • Collagen / chemistry
  • Collagen / metabolism*
  • Fibroblasts
  • Focal Adhesions
  • Gelsolin / metabolism*
  • Humans
  • Mice
  • Nonmuscle Myosin Type IIA / genetics
  • Nonmuscle Myosin Type IIA / metabolism*
  • Phagocytosis / physiology*
  • RNA Interference
  • RNA, Small Interfering

Substances

  • Actins
  • Gelsolin
  • RNA, Small Interfering
  • Collagen
  • Nonmuscle Myosin Type IIA
  • Calcium