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The role of talin in LFA-1 function in cell-mediated cytotoxicity Mace, Emily Margaret
Abstract
Natural killer (NK) cells and cytotoxic T lymphocytes (CTLs) are effectors of cell-mediated cytotoxicity towards virally infected and tumourigenic cells. The integrin leukocyte function associated antigen-1 (LFA-1) is required for the adhesion of effector cells to their targets. In addition, LFA-1 transduces signals resulting in actin polymerization. We show that in both CTLs and NK cells, LFA-1 ligand binding results in the recruitment of actin, the cytoskeletal adaptor talin, and the activator of actin nucleation Wiskott-Aldrich Syndrome protein (WASP). We used talin-knockout (KO) NK cells to demonstrate that talin is required for LFA-1 mediated adhesion and polarization towards the target cell. This actin polarization is a prerequisite for subsequent steps leading to cytotoxicity, including the translocation of cytotoxic granules. Further analysis of the LFA-1 mediated signaling that leads to actin polymerization shows that talin recruits proteins that catalyze de novo actin formation. Talin forms a complex with vinculin and the actin-nucleator Arp2/3, and talin is required for the movement of these proteins to LFA-1 following LFA-1 binding to ICAM-1. In addition, talin binds the phosphatidylinositol phosphate kinase PIPKIγ and talin is required for the localized production of phosphatidylinositol 4,5 bisphosphate (PIP₂) following LFA-1 ligation. This production of PIP₂ is required for the recruitment of WASP, which in turn activates Arp2/3 to polymerize actin. Thus we have demonstrated a critical role for talin in the actin polarization that is required for cell-mediated cytotoxicity and elucidated the mechanism of LFA-1 mediated actin polymerization.
Item Metadata
Title |
The role of talin in LFA-1 function in cell-mediated cytotoxicity
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2010
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Description |
Natural killer (NK) cells and cytotoxic T lymphocytes (CTLs) are effectors of cell-mediated cytotoxicity towards virally infected and tumourigenic cells. The integrin leukocyte function associated antigen-1 (LFA-1) is required for the adhesion of effector cells to their targets. In addition, LFA-1 transduces signals resulting in actin polymerization. We show that in both CTLs and NK cells, LFA-1 ligand binding results in the recruitment of actin, the cytoskeletal adaptor talin, and the activator of actin nucleation Wiskott-Aldrich Syndrome protein (WASP). We used talin-knockout (KO) NK cells to demonstrate that talin is required for LFA-1 mediated adhesion and polarization towards the target cell. This actin polarization is a prerequisite for subsequent steps leading to cytotoxicity, including the translocation of cytotoxic granules. Further analysis of the LFA-1 mediated signaling that leads to actin polymerization shows that talin recruits proteins that catalyze de novo actin formation. Talin forms a complex with vinculin and the actin-nucleator Arp2/3, and talin is required for the movement of these proteins to LFA-1 following LFA-1 binding to ICAM-1. In addition, talin binds the phosphatidylinositol phosphate kinase PIPKIγ and talin is required for the localized production of phosphatidylinositol 4,5 bisphosphate (PIP₂) following LFA-1 ligation. This production of PIP₂ is required for the recruitment of WASP, which in turn activates Arp2/3 to polymerize actin. Thus we have demonstrated a critical role for talin in the actin polarization that is required for cell-mediated cytotoxicity and elucidated the mechanism of LFA-1 mediated actin polymerization.
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Genre | |
Type | |
Language |
eng
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Date Available |
2010-04-01
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Provider |
Vancouver : University of British Columbia Library
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Rights |
Attribution-NonCommercial-NoDerivatives 4.0 International
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DOI |
10.14288/1.0070938
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2010-05
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Campus | |
Scholarly Level |
Graduate
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Rights URI | |
Aggregated Source Repository |
DSpace
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Rights
Attribution-NonCommercial-NoDerivatives 4.0 International