title: Cation type specific cell remodeling regulates attachment strength.
abstract: Single-molecule experiments indicate that integrin affinity is cation-type-dependent, but in spread cells integrins are engaged in complex focal adhesions (FAs), which can also regulate affinity. To better understand cation-type-dependent adhesion in fully spread cells, we investigated attachment strength by application of external shear. While cell attachment strength is indeed modulated by cations, the regulation of integrin-mediated adhesion is also exceedingly complex, cell specific, and niche dependent. In the presence of magnesium only, fibroblasts and fibrosarcoma cells remodel their cytoskeleton to align in the direction of applied shear in an α5-integrin/fibronectin-dependent manner, which allows them to withstand higher shear. In the presence of calcium or on collagen in modest shear, fibroblasts undergo piecewise detachment but fibrosarcoma cells exhibit increased attachment strength. These data augment the current understanding of force-mediated detachment by suggesting a dynamic interplay in situ between cell adhesion and integrins depending on local niche cation conditions.
authors.affiliation: Department of Bioengineering, Institute of Engineering in Medicine, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Alexander
authors.initials: A
authors.lastname: Fuhrmann
authors.affiliation: Department of Bioengineering, Institute of Engineering in Medicine, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Julie
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Bioengineering, Institute of Engineering in Medicine, University of California San Diego, La Jolla, California, United States of America; Department of Medicine, Institute of Engineering in Medicine, University of California San Diego, La Jolla, California, United States of America; Sanford Consortium for Regenerative Medicine, La Jolla, California, United States of America.
authors.forename: Shu
authors.initials: S
authors.lastname: Chien
authors.affiliation: Department of Bioengineering, Institute of Engineering in Medicine, University of California San Diego, La Jolla, California, United States of America; Sanford Consortium for Regenerative Medicine, La Jolla, California, United States of America.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Engler
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D002413:Cations, Divalent; D002448:Cell Adhesion / Q000502:physiology; D045744:Cell Line, Tumor; D003094:Collagen / Q000737:chemistry / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism* / Q000648:ultrastructure; D005353:Fibronectins / Q000737:chemistry / Q000378:metabolism; D022001:Focal Adhesions / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D016023:Integrins / Q000737:chemistry / Q000378:metabolism; D008274:Magnesium / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D041681:NIH 3T3 Cells; D012212:Rheology
chemical_list: D002413:Cations, Divalent; D005353:Fibronectins; D016023:Integrins; D003094:Collagen; D008274:Magnesium; D002118:Calcium