Anti-correlation of HER2 and focal adhesion complexes in the plasma membrane

PLoS One. 2020 Jun 8;15(6):e0234430. doi: 10.1371/journal.pone.0234430. eCollection 2020.

Abstract

Excess presence of the human epidermal growth factor receptor 2 (HER2) as well as of the focal adhesion protein complexes are associated with increased proliferation, migratory, and invasive behavior of cancer cells. A cross-regulation between HER2 and integrin signaling pathways has been found, but the exact mechanism remains elusive. Here, we investigated whether HER2 colocalizes with focal adhesion complexes on breast cancer cells overexpressing HER2. For this purpose, vinculin or talin green fluorescent protein (GFP) fusion proteins, both key constituents of focal adhesions, were expressed in breast cancer cells. HER2 was either extracellularly or intracellularly labeled with fluorescent quantum dots nanoparticles (QDs). The cell-substrate interface was analyzed at the location of the focal adhesions by means of total internal reflection fluorescent microscopy or correlative fluorescence- and scanning transmission electron microscopy. Expression of HER2 at the cell-substrate interface was only observed upon intracellular labeling, and was heterogeneous with both HER2-enriched and -low regions. In contrast to an expected enrichment of HER2 at focal adhesions, an anti-correlated expression pattern was observed for talin and HER2. Our findings suggest a spatial anti-correlation between HER2 and focal adhesion complexes for adherent cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Adhesion
  • Cell Line, Tumor
  • Cell Membrane / metabolism*
  • Cell Membrane / ultrastructure
  • Erb-b2 Receptor Tyrosine Kinases / analysis
  • Erb-b2 Receptor Tyrosine Kinases / metabolism*
  • Focal Adhesions / metabolism*
  • Focal Adhesions / ultrastructure
  • Genes, Reporter
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Humans
  • Microscopy, Electron, Scanning Transmission
  • Microscopy, Fluorescence
  • Recombinant Fusion Proteins / analysis
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Spatial Analysis*
  • Talin / analysis
  • Talin / genetics
  • Talin / metabolism
  • Vinculin / analysis
  • Vinculin / genetics
  • Vinculin / metabolism

Substances

  • Green Fluorescent Proteins
  • Erb-b2 Receptor Tyrosine Kinases
  • Recombinant Fusion Proteins
  • Talin
  • Vinculin
  • VCL protein, human
  • ERBB2 protein, human