title: Decoding Cytoskeleton-Anchored and Non-Anchored Receptors from Single-Cell Adhesion Force Data.
abstract: Complementary to parameters established for cell-adhesion force curve analysis, we evaluated the slope before a force step together with the distance from the surface at which the step occurs and visualized the result in a two-dimensional density plot. This new tool allows detachment steps of long membrane tethers to be distinguished from shorter jumplike force steps, which are typical for cytoskeleton-anchored bonds. A prostate cancer cell line (PC3) immobilized on an atomic-force-microscopy sensor interacted with three different substrates: collagen-I (Col-I), bovine serum albumin, and a monolayer of bone marrow-derived stem cells (SCP1). To address PC3 cells' predominant Col-I binding molecules, an antibody-blocking β1-integrin was used. Untreated PC3 cells on Col-I or SCP1 cells, which express Col-I, predominantly showed jumps in their force curves, while PC3 cells on bovine-serum-albumin- and antibody-treated PC3 cells showed long membrane tethers. The probability density plots thus revealed that β1-integrin-specific interactions are predominately anchored to the cytoskeleton, while the nonspecific interactions are mainly membrane-anchored. Experiments with latrunculin-A-treated PC3 cells corroborated these observations. The plots thus reveal details of the anchoring of bonds to the cell and provide a better understanding of receptor-ligand interactions.
authors.affiliation: Experimental Surgery and Regenerative Medicine, Department of Surgery, Ludwig-Maximilians-Universität München, Munich, Germany; Center for NanoScience, Ludwig-Maximilians-Universität München, Munich, Germany; Center for Applied Tissue Engineering and Regenerative Medicine, University of Applied Sciences, Munich, Germany.
authors.forename: Ediz
authors.initials: E
authors.lastname: Sariisik
authors.affiliation: Experimental Surgery and Regenerative Medicine, Department of Surgery, Ludwig-Maximilians-Universität München, Munich, Germany.
authors.forename: Cvetan
authors.initials: C
authors.lastname: Popov
authors.affiliation: Center for NanoScience, Ludwig-Maximilians-Universität München, Munich, Germany.
authors.forename: Jochen P
authors.initials: JP
authors.lastname: Müller
authors.affiliation: Experimental Surgery and Regenerative Medicine, Department of Surgery, Ludwig-Maximilians-Universität München, Munich, Germany; Center for Applied Tissue Engineering and Regenerative Medicine, University of Applied Sciences, Munich, Germany.
authors.forename: Denitsa
authors.initials: D
authors.lastname: Docheva
authors.affiliation: Center for NanoScience, Ludwig-Maximilians-Universität München, Munich, Germany; Center for Applied Tissue Engineering and Regenerative Medicine, University of Applied Sciences, Munich, Germany.
authors.forename: Hauke
authors.initials: H
authors.lastname: Clausen-Schaumann
authors.affiliation: Center for NanoScience, Ludwig-Maximilians-Universität München, Munich, Germany; Center for Applied Tissue Engineering and Regenerative Medicine, University of Applied Sciences, Munich, Germany. Electronic address: martin.benoit@physik.uni-muenchen.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Benoit
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000378:metabolism; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003094:Collagen / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism*; D039222:Integrin alpha1beta1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D008297:Male; D018625:Microscopy, Atomic Force; D011471:Prostatic Neoplasms; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism
chemical_list: D039222:Integrin alpha1beta1; D012710:Serum Albumin, Bovine; D003094:Collagen