Macrophage mesenchymal migration requires podosome stabilization by filamin A

J Biol Chem. 2012 Apr 13;287(16):13051-62. doi: 10.1074/jbc.M111.307124. Epub 2012 Feb 9.

Abstract

Filamin A (FLNa) is a cross-linker of actin filaments and serves as a scaffold protein mostly involved in the regulation of actin polymerization. It is distributed ubiquitously, and null mutations have strong consequences on embryonic development in humans, with organ defects which suggest deficiencies in cell migration. We have reported previously that macrophages, the archetypal migratory cells, use the protease- and podosome-dependent mesenchymal migration mode in dense three-dimensional environments, whereas they use the protease- and podosome-independent amoeboid mode in more porous matrices. Because FLNa has been shown to localize to podosomes, we hypothesized that the defects seen in patients carrying FLNa mutations could be related to the capacity of certain cell types to form podosomes. Using strategies based on FLNa knock-out, knockdown, and rescue, we show that FLNa (i) is involved in podosome stability and their organization as rosettes and three-dimensional podosomes, (ii) regulates the proteolysis of the matrix mediated by podosomes in macrophages, (iii) is required for podosome rosette formation triggered by Hck, and (iv) is necessary for mesenchymal migration but dispensable for amoeboid migration. These new functions assigned to FLNa, particularly its role in mesenchymal migration, could be directly related to the defects in cell migration described during the embryonic development in FLNa-defective patients.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Animals
  • Cell Movement / immunology*
  • Contractile Proteins / genetics
  • Contractile Proteins / metabolism*
  • Fibroblasts / cytology
  • Filamins
  • Humans
  • Macrophages / cytology*
  • Macrophages / metabolism*
  • Macrophages / ultrastructure
  • Mechanotransduction, Cellular / physiology
  • Mesoderm / cytology
  • Mice
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism*
  • NIH 3T3 Cells
  • Proto-Oncogene Proteins c-hck / metabolism
  • RNA, Small Interfering / genetics

Substances

  • Contractile Proteins
  • Filamins
  • Microfilament Proteins
  • RNA, Small Interfering
  • Hck protein, mouse
  • Proto-Oncogene Proteins c-hck