A dynamic podosome-like structure of epithelial cells

Laura Spinardi, Jens Rietdorf, Lucio Nitsch, Maria Bono, Carlo Tacchetti, Michael Way, Pier Carlo Marchisio

Research output: Contribution to journalArticlepeer-review


Focal contacts and hemidesmosomes are cell-matrix adhesion structures of cultured epithelial cells. While focal contacts link the extracellular matrix to microfilaments, hemidesmosomes make connections with intermediate filaments. We have analyzed hemidesmosome assembly in 804G carcinoma cells. Our data show that hemidesmosomes are organized around a core of actin filaments that appears early during cell adhesion. These actin structures look similar to podosomes described in cells of mesenchymal origin. These podosome-like structures are distinct from focal contacts and specifically contain Arp3 (Arp2/3 complex), cortactin, dynamin, gelsolin, N-WASP, VASP, Grb2 and src-like kinase(s). The integrin α3β1 is localized circularly around F-actin cores and co-distributes with paxillin, vinculin, and zyxin. We also show that the maintenance of the actin core and hemidesmosomes is dependent on actin polymerization, src-family kinases, and Grb2, but not on microtubules. Video microscopy analysis reveals that assembly of hemidesmosomes is preceded by recruitment of β4 integrin subunit to the actin core before its positioning at hemidesmosomes. When 804G cells are induced to migrate, actin cores as well as hemidesmosomes disappear and β4 integrin subunit becomes co-localized with dynamic actin at leading edges. We show that podosome-like structures are not unique to cells of mesenchymal origin, but also appear in epithelial cells, where they seem to be related to basement membrane adhesion.

Original languageEnglish
Pages (from-to)360-374
Number of pages15
JournalExperimental Cell Research
Issue number2
Publication statusPublished - May 1 2004


  • Epithelial adhesion
  • Hemidesmosome
  • Integrin α6β4
  • Motility
  • Podosome

ASJC Scopus subject areas

  • Cell Biology


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