The multi-FERM-domain-containing protein FrmA is required for turnover of paxillin-adhesion sites during cell migration of Dictyostelium

J Cell Sci. 2008 Apr 15;121(Pt 8):1159-64. doi: 10.1242/jcs.021725. Epub 2008 Mar 18.

Abstract

FERM domain proteins, including talins, ERMs, FAK and certain myosins, regulate connections between the plasma membrane, cytoskeleton and extracellular matrix. Here we show that FrmA, a Dictyostelium discoideum protein containing two talin-like FERM domains, plays a major role in normal cell shape, cell-substrate adhesion and actin cytoskeleton organisation. Using total internal reflection fluorescence (TIRF) microscopy we show that FrmA-null cells are more adherent to substrate than wild-type cells because of an increased number, persistence and mislocalisation of paxillin-rich cell-substrate adhesions, which is associated with decreased motility. We show for the first time that talinA colocalises with paxillin at the distal ends of filopodia to form cell-substrate adhesions and indeed arrives prior to paxillin. After a period of colocalisation, talin leaves the adhesion site followed by paxillin. Whereas talinA-rich spots turnover prior to the arrival of the main body of the cell, paxillin-rich spots turn over as the main body of the cell passes over it. In FrmA-null cells talinA initially localises to cell-substrate adhesion sites at the distal ends of filopodia but paxillin is instead localised to stabilised adhesion sites at the periphery of the main cell body. This suggests a model for cell-substrate adhesion in Dictyostelium whereby the talin-like FERM domains of FrmA regulate the temporal and spatial control of talinA and paxillin at cell-substrate adhesion sites, which in turn controls adhesion and motility.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Base Sequence
  • Cell Movement*
  • DNA Primers
  • Dictyostelium / cytology*
  • Fluorescent Antibody Technique
  • Paxillin / metabolism*
  • Protozoan Proteins / physiology*

Substances

  • Actins
  • DNA Primers
  • Paxillin
  • Protozoan Proteins