title: FAK and paxillin dynamics at focal adhesions in the protrusions of migrating cells.
abstract: Cell migration requires the fine spatiotemporal integration of many proteins that regulate the fundamental processes that drive cell movement. Focal adhesion (FA) dynamics is a continuous process involving coordination between FA and actin cytoskeleton, which is essential for cell migration. We studied the spatiotemporal relationship between the dynamics of focal adhesion kinase (FAK) and paxillin at FAs in the protrusion of living endothelial cells. Concurrent dual-color imaging showed that FAK was assembled at FA first, which was followed by paxillin recruitment to the FA. By tracking and quantifying FAK and paxillin in migrating cells, the normalized FAK/Paxillin fluorescence intensity (FI) ratio is > 1 (≈ 4 fold) at cell front, ≈ 1 at cell center, and < 1 at cell rear. The significantly higher FAK FI than paxillin FI at cell front indicates that the assembly of FAK-FAs occurs ahead of paxillin at cell front. To determine the time difference between the assemblies of FAK and paxillin at nascent FAs, FAs containing both FAK and paxillin were quantified by image analysis and time correlation. The results show that FAK assembles at the nascent FAs earlier than paxillin in the protrusions at cell front.
authors.affiliation: 1] Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA [2] Institute of Engineering in Medicine University of California, San Diego, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Ying-Li
authors.initials: YL
authors.lastname: Hu
authors.affiliation: 1] Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA [2] Institute of Engineering in Medicine University of California, San Diego, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Shaoying
authors.initials: S
authors.lastname: Lu
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Kai W
authors.initials: KW
authors.lastname: Szeto
authors.affiliation: Beckman Institute, University of Illinois, Urbana-Champaign, Urbana, IL 61801 USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.affiliation: 1] Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA [2] Institute of Engineering in Medicine University of California, San Diego, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Yingxiao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: 1] Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA [2] Institute of Engineering in Medicine University of California, San Diego, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Lasheras
authors.affiliation: 1] Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA [2] Institute of Engineering in Medicine University of California, San Diego, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Shu
authors.initials: S
authors.lastname: Chien
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002465:Cell Movement; D002478:Cells, Cultured; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D022001:Focal Adhesions / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D051419:Paxillin / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D059008:Time-Lapse Imaging; D000097573:Red Fluorescent Protein
chemical_list: D000199:Actins; D051416:Focal Adhesion Protein-Tyrosine Kinases; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D051419:Paxillin; D011993:Recombinant Fusion Proteins; D000097573:Red Fluorescent Protein
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