The asymmetric self-assembly mechanism of adherens junctions: a cellular push-pull unit.
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.
Brevier
Julien
J
Laboratoire de Spectrométrie Physique, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5588, Université Joseph Fourier, 38402 Saint-Martin d'Hères, France.
Montero
David
D
Svitkina
Tatyana
T
Riveline
Daniel
D
D000199:Actins / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D000205:Actomyosin / Q000378:metabolism; D022005:Adherens Junctions / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D000818:Animals; D015703:Antigens, CD / Q000235:genetics; D001696:Biomechanical Phenomena; D016466:CHO Cells; D015820:Cadherins / Q000235:genetics; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D006224:Cricetinae; D003412:Cricetulus; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D008856:Microscopy, Fluorescence; D011554:Pseudopodia / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D022502:Stress Fibers / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D014162:Transfection; D020744:rac GTP-Binding Proteins / Q000235:genetics; D000099152:Cadherin 5
D000199:Actins; D000205:Actomyosin; D015703:Antigens, CD; D015820:Cadherins; D049452:Green Fluorescent Proteins; D020744:rac GTP-Binding Proteins; D000099152:Cadherin 5