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A talin-dependent LFA-1 focal zone is formed by rapidly migrating T lymphocytes.

Smith A, Carrasco YR, Stanley P, Kieffer N, Batista FD, Hogg N - J. Cell Biol. (2005)

Bottom Line: Talin is essential for the stability and formation of the LFA-1 zone.Disruption of the talin-integrin link leads to loss of zone integrity and a substantial decrease in speed of migration on ICAM-1.This adhesive structure, which differs from the previously described integrin-containing attachments displayed by many other cell types, we have termed the "focal zone."

View Article: PubMed Central - PubMed

Affiliation: Leukocyte Adhesion Laboratory, Cancer Research UK London Research Institute, London WC2A 3PX, England, UK.

ABSTRACT
Cells such as fibroblasts and endothelial cells migrate through the coordinated responses of discrete integrin-containing focal adhesions and complexes. In contrast, little is known about the organization of integrins on the highly motile T lymphocyte. We have investigated the distribution, activity, and cytoskeletal linkage of the integrin lymphocyte function associated antigen-1 (LFA-1) on human T lymphocytes migrating on endothelial cells and on ligand intercellular adhesion molecule-1 (ICAM-1). The pattern of total LFA-1 varies from low expression in the lamellipodia to high expression in the uropod. However, high affinity, clustered LFA-1 is restricted to a mid-cell zone that remains stable over time and over a range of ICAM-1 densities. Talin is essential for the stability and formation of the LFA-1 zone. Disruption of the talin-integrin link leads to loss of zone integrity and a substantial decrease in speed of migration on ICAM-1. This adhesive structure, which differs from the previously described integrin-containing attachments displayed by many other cell types, we have termed the "focal zone."

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Confocal image of a T cell migrating in the presence of 5 mM MgCl2 on a target cell expressing ICAM-1. T cells labeled with Alexa 488 nonblocking anti–LFA-1 Fabs and migrating on TNF-α–activated HUVECs. (A) Phase images of the pattern of migration of four T cells (1–4) over 3 min. (B) False color images of the same four T cells showing expression levels of LFA-1 (highest [white] to lowest [blue]). The asterisk denotes the leading edge of each cell. (C) T cell (white outline) migrating on ICAM-1–transfected COS-7 cells (the asterisk denotes the T cell leading edge). (a) T cell labeled with anti–LFA-1 mAb (red). (b) COS-7 cells expressing ICAM-1-GFP (green). (c) Merge of the two images in panels a and b. Colocalization of LFA-1 and ICAM-1 can be observed in the mid-cell region. All images were taken with a 63× oil immersion objective. Bars, 10 μm. (d) Quantitation of ICAM-1 density in focal zone (black bar) compared with lamellar region (gray bar) on migrating T cells (n = 9; ±SD). *, P < 0.001.
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fig1: Confocal image of a T cell migrating in the presence of 5 mM MgCl2 on a target cell expressing ICAM-1. T cells labeled with Alexa 488 nonblocking anti–LFA-1 Fabs and migrating on TNF-α–activated HUVECs. (A) Phase images of the pattern of migration of four T cells (1–4) over 3 min. (B) False color images of the same four T cells showing expression levels of LFA-1 (highest [white] to lowest [blue]). The asterisk denotes the leading edge of each cell. (C) T cell (white outline) migrating on ICAM-1–transfected COS-7 cells (the asterisk denotes the T cell leading edge). (a) T cell labeled with anti–LFA-1 mAb (red). (b) COS-7 cells expressing ICAM-1-GFP (green). (c) Merge of the two images in panels a and b. Colocalization of LFA-1 and ICAM-1 can be observed in the mid-cell region. All images were taken with a 63× oil immersion objective. Bars, 10 μm. (d) Quantitation of ICAM-1 density in focal zone (black bar) compared with lamellar region (gray bar) on migrating T cells (n = 9; ±SD). *, P < 0.001.

Mentions: To understand the role of LFA-1 in T cell migration, we activated LFA-1 directly with Mg2+ and followed the random migration of the cells on a monolayer of ICAM-1–expressing human umbilical vein endothelial cells (HUVECs). At the HUVEC interface, T cell LFA-1 displayed a heterogeneous distribution with low levels in the lamellipodia and a concentrated area corresponding to the mid-region of the cell (Fig. 1, A and B). The uropod at the rear of the cell formed an elevated nonadherent cell protrusion that made minimal contact with the HUVECs. The distribution of LFA-1 at the interface remained constant as the cells migrated (Video 1, available at http://www.jcb.org/cgi/content/full/jcb.200412032/DC1). The addition of function blocking anti–LFA-1 (mAb 38) resulted in the loss of LFA-1 redistribution to the mid-cell region and reduced adhesion to the HUVECs (unpublished data).


A talin-dependent LFA-1 focal zone is formed by rapidly migrating T lymphocytes.

Smith A, Carrasco YR, Stanley P, Kieffer N, Batista FD, Hogg N - J. Cell Biol. (2005)

Confocal image of a T cell migrating in the presence of 5 mM MgCl2 on a target cell expressing ICAM-1. T cells labeled with Alexa 488 nonblocking anti–LFA-1 Fabs and migrating on TNF-α–activated HUVECs. (A) Phase images of the pattern of migration of four T cells (1–4) over 3 min. (B) False color images of the same four T cells showing expression levels of LFA-1 (highest [white] to lowest [blue]). The asterisk denotes the leading edge of each cell. (C) T cell (white outline) migrating on ICAM-1–transfected COS-7 cells (the asterisk denotes the T cell leading edge). (a) T cell labeled with anti–LFA-1 mAb (red). (b) COS-7 cells expressing ICAM-1-GFP (green). (c) Merge of the two images in panels a and b. Colocalization of LFA-1 and ICAM-1 can be observed in the mid-cell region. All images were taken with a 63× oil immersion objective. Bars, 10 μm. (d) Quantitation of ICAM-1 density in focal zone (black bar) compared with lamellar region (gray bar) on migrating T cells (n = 9; ±SD). *, P < 0.001.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2171377&req=5

fig1: Confocal image of a T cell migrating in the presence of 5 mM MgCl2 on a target cell expressing ICAM-1. T cells labeled with Alexa 488 nonblocking anti–LFA-1 Fabs and migrating on TNF-α–activated HUVECs. (A) Phase images of the pattern of migration of four T cells (1–4) over 3 min. (B) False color images of the same four T cells showing expression levels of LFA-1 (highest [white] to lowest [blue]). The asterisk denotes the leading edge of each cell. (C) T cell (white outline) migrating on ICAM-1–transfected COS-7 cells (the asterisk denotes the T cell leading edge). (a) T cell labeled with anti–LFA-1 mAb (red). (b) COS-7 cells expressing ICAM-1-GFP (green). (c) Merge of the two images in panels a and b. Colocalization of LFA-1 and ICAM-1 can be observed in the mid-cell region. All images were taken with a 63× oil immersion objective. Bars, 10 μm. (d) Quantitation of ICAM-1 density in focal zone (black bar) compared with lamellar region (gray bar) on migrating T cells (n = 9; ±SD). *, P < 0.001.
Mentions: To understand the role of LFA-1 in T cell migration, we activated LFA-1 directly with Mg2+ and followed the random migration of the cells on a monolayer of ICAM-1–expressing human umbilical vein endothelial cells (HUVECs). At the HUVEC interface, T cell LFA-1 displayed a heterogeneous distribution with low levels in the lamellipodia and a concentrated area corresponding to the mid-region of the cell (Fig. 1, A and B). The uropod at the rear of the cell formed an elevated nonadherent cell protrusion that made minimal contact with the HUVECs. The distribution of LFA-1 at the interface remained constant as the cells migrated (Video 1, available at http://www.jcb.org/cgi/content/full/jcb.200412032/DC1). The addition of function blocking anti–LFA-1 (mAb 38) resulted in the loss of LFA-1 redistribution to the mid-cell region and reduced adhesion to the HUVECs (unpublished data).

Bottom Line: Talin is essential for the stability and formation of the LFA-1 zone.Disruption of the talin-integrin link leads to loss of zone integrity and a substantial decrease in speed of migration on ICAM-1.This adhesive structure, which differs from the previously described integrin-containing attachments displayed by many other cell types, we have termed the "focal zone."

View Article: PubMed Central - PubMed

Affiliation: Leukocyte Adhesion Laboratory, Cancer Research UK London Research Institute, London WC2A 3PX, England, UK.

ABSTRACT
Cells such as fibroblasts and endothelial cells migrate through the coordinated responses of discrete integrin-containing focal adhesions and complexes. In contrast, little is known about the organization of integrins on the highly motile T lymphocyte. We have investigated the distribution, activity, and cytoskeletal linkage of the integrin lymphocyte function associated antigen-1 (LFA-1) on human T lymphocytes migrating on endothelial cells and on ligand intercellular adhesion molecule-1 (ICAM-1). The pattern of total LFA-1 varies from low expression in the lamellipodia to high expression in the uropod. However, high affinity, clustered LFA-1 is restricted to a mid-cell zone that remains stable over time and over a range of ICAM-1 densities. Talin is essential for the stability and formation of the LFA-1 zone. Disruption of the talin-integrin link leads to loss of zone integrity and a substantial decrease in speed of migration on ICAM-1. This adhesive structure, which differs from the previously described integrin-containing attachments displayed by many other cell types, we have termed the "focal zone."

Show MeSH
Related in: MedlinePlus