Green fluorescent protein-mTalin causes defects in actin organization and cell expansion in Arabidopsis and inhibits actin depolymerizing factor's actin depolymerizing activity in vitro

Plant Physiol. 2004 Dec;136(4):3990-8. doi: 10.1104/pp.104.050799. Epub 2004 Nov 24.

Abstract

Expression of green fluorescent protein (GFP) linked to an actin binding domain is a commonly used method for live cell imaging of the actin cytoskeleton. One of these chimeric proteins is GFP-mTalin (GFP fused to the actin binding domain of mouse talin). Although it has been demonstrated that GFP-mTalin colocalizes with the actin cytoskeleton, its effect on actin dynamics and cell expansion has not been studied in detail. We created Arabidopsis (Arabidopsis thaliana) plants harboring alcohol inducible GFP-mTalin constructs to assess the effect of GFP-mTalin expression in vivo. We focused on the growing root hair as this is a model cell for studying cell expansion and root hair tip growth that requires a highly dynamic and polar actin cytoskeleton. We show that alcohol inducible expression of GFP-mTalin in root hairs causes severe defects in actin organization, resulting in either the termination of growth, cell death, and/or changes in cell shape. Fluorescence recovery after photobleaching experiments demonstrate that the interaction of GFP-mTalin and actin filaments is highly dynamic. To assess how GFP-mTalin affects actin dynamics we performed cosedimentation assays of GFP-mTalin with actin on its own or in the presence of the actin modulating protein, actin depolymerizing factor. We show that that GFP-mTalin does not affect actin polymerization but that it does inhibit the actin depolymerizing activity of actin depolymerizing factor. These observations demonstrate that GFP-mTalin can affect cell expansion, actin organization, and the interaction of actin binding proteins with actin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Depolymerizing Factors
  • Actins / chemistry
  • Actins / metabolism*
  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism
  • Cell Enlargement
  • Cytoskeleton / chemistry
  • Cytoskeleton / metabolism
  • Destrin
  • Gene Expression Regulation, Plant
  • Green Fluorescent Proteins
  • Microfilament Proteins / metabolism*
  • Plant Roots / growth & development
  • Plant Roots / ultrastructure
  • Plants, Genetically Modified
  • Talin / chemistry
  • Talin / metabolism*
  • Time Factors

Substances

  • Actin Depolymerizing Factors
  • Actins
  • Destrin
  • Microfilament Proteins
  • Talin
  • Tln1 protein, mouse
  • Green Fluorescent Proteins