Nanoscale architecture of integrin-based cell adhesions.
Cell adhesions to the extracellular matrix (ECM) are necessary for morphogenesis, immunity and wound healing. Focal adhesions are multifunctional organelles that mediate cell-ECM adhesion, force transmission, cytoskeletal regulation and signalling. Focal adhesions consist of a complex network of trans-plasma-membrane integrins and cytoplasmic proteins that form a <200-nm plaque linking the ECM to the actin cytoskeleton. The complexity of focal adhesion composition and dynamics implicate an intricate molecular machine. However, focal adhesion molecular architecture remains unknown. Here we used three-dimensional super-resolution fluorescence microscopy (interferometric photoactivated localization microscopy) to map nanoscale protein organization in focal adhesions. Our results reveal that integrins and actin are vertically separated by a ∼40-nm focal adhesion core region consisting of multiple protein-specific strata: a membrane-apposed integrin signalling layer containing integrin cytoplasmic tails, focal adhesion kinase and paxillin; an intermediate force-transduction layer containing talin and vinculin; and an uppermost actin-regulatory layer containing zyxin, vasodilator-stimulated phosphoprotein and α-actinin. By localizing amino- and carboxy-terminally tagged talins, we reveal talin's polarized orientation, indicative of a role in organizing the focal adhesion strata. The composite multilaminar protein architecture provides a molecular blueprint for understanding focal adhesion functions.
National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Pakorn
P
Kanchanawong
Gleb
G
Shtengel
Ana M
AM
Pasapera
Ericka B
EB
Ramko
Michael W
MW
Davidson
Harald F
HF
Hess
Clare M
CM
Waterman
D000199:Actins / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion; D002460:Cell Line; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological
D000199:Actins; D016023:Integrins