Dissecting the molecular architecture of integrin adhesion sites by cryo-electron tomography.
Focal adhesions are integrin-based multiprotein complexes, several micrometres in diameter, that mechanically link the extracellular matrix with the termini of actin bundles. The molecular diversity of focal adhesions and their role in cell migration and matrix sensing has been extensively studied, but their ultrastructural architecture is still unknown. We present the first three-dimensional structural reconstruction of focal adhesions using cryo-electron tomography. Our analyses reveal that the membrane-cytoskeleton interaction at focal adhesions is mediated through particles located at the cell membrane and attached to actin fibres. The particles have diameters of 25 +/- 5 nm, and an average interspacing of approximately 45 nm. Treatment with the Rho-kinase inhibitor Y-27632 induces a rapid decrease in particle diameter, suggesting that they are highly mechanosensitive. Our findings clarify the internal architecture of focal adhesions at molecular resolution, and provide insights into their scaffolding and mechanosensory functions.
Patla
Israel
I
Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben Gurion University of the Negev, Be'er-Sheva 84120, Israel.
Volberg
Tova
T
Elad
Nadav
N
Hirschfeld-Warneken
Vera
V
Grashoff
Carsten
C
Fässler
Reinhard
R
Spatz
Joachim P
JP
Geiger
Benjamin
B
Medalia
Ohad
O
D008841:Actin Cytoskeleton / Q000378:metabolism; D000577:Amides / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D020285:Cryoelectron Microscopy / Q000379:methods*; D005347:Fibroblasts / Q000187:drug effects / Q000648:ultrastructure; D022001:Focal Adhesions / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D016023:Integrins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D010316:Particle Size; D051419:Paxillin / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D022502:Stress Fibers / Q000648:ultrastructure; D014054:Tomography / Q000379:methods*; D016596:Vinculin / Q000378:metabolism; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors
D000577:Amides; D016023:Integrins; D051419:Paxillin; D047428:Protein Kinase Inhibitors; C496063:Pxn protein, rat; D011725:Pyridines; C488956:Vcl protein, rat; D016596:Vinculin; C108830:Y 27632; D054460:rho-Associated Kinases