The asymmetric self-assembly mechanism of adherens junctions: a cellular push-pull unit

Phys Biol. 2008 Apr 1;5(1):016005. doi: 10.1088/1478-3975/5/1/016005.

Abstract

To form adherens junctions (AJ), cells first establish contact by sending out lamellipodia onto neighboring cells. We investigated the role of contacting cells in AJ assembly by studying an asymmetric AJ motif: finger-like AJ extending across the cell-cell interface. Using a cytoskeleton replica and immunofluorescence, we observed that actin bundles embedded in the lamellipodia are co-localized with stress fibers in the neighboring cell at the AJ. This suggests that donor lamellipodia present actin fingers, which are stabilized by acceptor lamellae via acto-myosin contractility. Indeed, we show that changes in actin network geometry promoted by Rac overexpression lead to corresponding changes in AJ morphology. Moreover, contractility inhibition and enhancement (via drugs or local traction) lead respectively to the disappearance and further growth of AJ fingers. Thus, we propose that receiving lamellae exert a local pull on AJ, promoting further polymerization of the donor actin bundles. In spite of different compositions, AJ and focal contacts both act as cellular mechanosensors.

Publication types

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

MeSH terms

  • Actins / genetics
  • Actins / metabolism*
  • Actins / ultrastructure
  • Actomyosin / metabolism
  • Adherens Junctions / drug effects
  • Adherens Junctions / physiology
  • Adherens Junctions / ultrastructure*
  • Animals
  • Antigens, CD / genetics
  • Biomechanical Phenomena
  • CHO Cells
  • Cadherins / genetics
  • Cell Adhesion / drug effects
  • Cell Adhesion / physiology
  • Cricetinae
  • Cricetulus
  • Endothelial Cells* / cytology
  • Endothelial Cells* / metabolism
  • Endothelial Cells* / ultrastructure
  • Green Fluorescent Proteins / genetics
  • Humans
  • Microscopy, Fluorescence
  • Pseudopodia / drug effects
  • Pseudopodia / physiology
  • Pseudopodia / ultrastructure*
  • Stress Fibers / drug effects
  • Stress Fibers / metabolism
  • Stress Fibers / ultrastructure
  • Transfection
  • rac GTP-Binding Proteins / genetics

Substances

  • Actins
  • Antigens, CD
  • Cadherins
  • cadherin 5
  • Green Fluorescent Proteins
  • Actomyosin
  • rac GTP-Binding Proteins