title: Revealing early steps of alpha2beta1 integrin-mediated adhesion to collagen type I by using single-cell force spectroscopy.
abstract: We have characterized early steps of alpha(2)beta(1) integrin-mediated cell adhesion to a collagen type I matrix by using single-cell force spectroscopy. In agreement with the role of alpha(2)beta(1) as a collagen type I receptor, alpha(2)beta(1)-expressing Chinese hamster ovary (CHO)-A2 cells spread rapidly on the matrix, whereas alpha(2)beta(1)-negative CHO wild-type cells adhered poorly. Probing CHO-A2 cell detachment forces over a contact time range of 600 s revealed a nonlinear adhesion response. During the first 60 s, cell adhesion increased slowly, and forces associated with the smallest rupture events were consistent with the breakage of individual integrin-collagen bonds. Above 60 s, a fraction of cells rapidly switched into an activated adhesion state marked by up to 10-fold increased detachment forces. Elevated overall cell adhesion coincided with a rise of the smallest rupture forces above the value required to break a single-integrin-collagen bond, suggesting a change from single to cooperative receptor binding. Transition into the activated adhesion mode and the increase of the smallest rupture forces were both blocked by inhibitors of actomyosin contractility. We therefore propose a two-step mechanism for the establishment of alpha(2)beta(1)-mediated adhesion as weak initial, single-integrin-mediated binding events are superseded by strong adhesive interactions involving receptor cooperativity and actomyosin contractility.
authors.affiliation: BioTechnological Center, University of Technology Dresden, 01307 Dresden, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Taubenberger
authors.forename: David A
authors.initials: DA
authors.lastname: Cisneros
authors.forename: Jens
authors.initials: J
authors.lastname: Friedrichs
authors.forename: Pierre-Henri
authors.initials: PH
authors.lastname: Puech
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Muller
authors.forename: Clemens M
authors.initials: CM
authors.lastname: Franz
mesh_terms: D000205:Actomyosin / Q000378:metabolism; D000577:Amides / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D001696:Biomechanical Phenomena; D016466:CHO Cells; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D024042:Collagen Type I / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D004791:Enzyme Inhibitors / Q000493:pharmacokinetics; D022001:Focal Adhesions / Q000378:metabolism; D006801:Humans; D038982:Integrin alpha2beta1 / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors; D018625:Microscopy, Atomic Force; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011725:Pyridines / Q000494:pharmacology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D054460:rho-Associated Kinases
chemical_list: D000577:Amides; D024042:Collagen Type I; D004791:Enzyme Inhibitors; D038982:Integrin alpha2beta1; D047908:Intracellular Signaling Peptides and Proteins; D011725:Pyridines; D011994:Recombinant Proteins; C108830:Y 27632; D000205:Actomyosin; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases