title: Lamellipodia are crucial for haptotactic sensing and response.
abstract: Haptotaxis is the process by which cells respond to gradients of substrate-bound cues, such as extracellular matrix proteins (ECM); however, the cellular mechanism of this response remains poorly understood and has mainly been studied by comparing cell behavior on uniform ECMs with different concentrations of components. To study haptotaxis in response to gradients, we utilized microfluidic chambers to generate gradients of the ECM protein fibronectin, and imaged the cell migration response. Lamellipodia are fan-shaped protrusions that are common in migrating cells. Here, we define a new function for lamellipodia and the cellular mechanism required for haptotaxis - differential actin and lamellipodial protrusion dynamics lead to biased cell migration. Modest differences in lamellipodial dynamics occurring over time periods of seconds to minutes are summed over hours to produce differential whole cell movement towards higher concentrations of fibronectin. We identify a specific subset of lamellipodia regulators as being crucial for haptotaxis. Numerous studies have linked components of this pathway to cancer metastasis and, consistent with this, we find that expression of the oncogenic Rac1 P29S mutation abrogates haptotaxis. Finally, we show that haptotaxis also operates through this pathway in 3D environments.
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: King
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Sreeja B
authors.initials: SB
authors.lastname: Asokan
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Haynes
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: Seth P
authors.initials: SP
authors.lastname: Zimmerman
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Rotty
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: James G
authors.initials: JG
authors.lastname: Alb
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Alicia
authors.initials: A
authors.lastname: Tagliatela
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Pharmacology, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC 27599, USA.
authors.forename: Devon R
authors.initials: DR
authors.lastname: Blake
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Howard Hughes Medical Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Irina P
authors.initials: IP
authors.lastname: Lebedeva
authors.affiliation: Department of Pharmacology, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC 27599, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Marston
authors.affiliation: Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Heath E
authors.initials: HE
authors.lastname: Johnson
authors.affiliation: King's College London, Randall Institute, London SE1 8RT, UK.
authors.forename: Maddy
authors.initials: M
authors.lastname: Parsons
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Norman E
authors.initials: NE
authors.lastname: Sharpless
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Kuhlman
authors.affiliation: Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Haugh
authors.affiliation: UNC Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA Howard Hughes Medical Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA jbear@email.unc.edu.
authors.forename: James E
authors.identifier: 0000-0002-8489-996X
authors.initials: JE
authors.lastname: Bear
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000818:Animals; D002633:Chemotaxis / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005353:Fibronectins / Q000494:pharmacology*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D022001:Focal Adhesions / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D019012:Integrin beta1 / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D011554:Pseudopodia / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D000075684:T-Lymphoma Invasion and Metastasis-inducing Protein 1; D051316:Wiskott-Aldrich Syndrome Protein / Q000378:metabolism; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000378:metabolism; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D005353:Fibronectins; D020662:Guanine Nucleotide Exchange Factors; D019012:Integrin beta1; D000075684:T-Lymphoma Invasion and Metastasis-inducing Protein 1; C513260:Tiam1 protein, mouse; D051316:Wiskott-Aldrich Syndrome Protein; D051300:Wiskott-Aldrich Syndrome Protein Family; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019061:src-Family Kinases; D020744:rac GTP-Binding Proteins
keywords: Arp2/3; Directed migration; Haptotaxis; Lamellipodia