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Endothelial cells use dynamic actin to facilitate lymphocyte transendothelial migration and maintain the monolayer barrier.

Mooren OL, Li J, Nawas J, Cooper JA - Mol. Biol. Cell (2014)

Bottom Line: The actin cytoskeleton of the endothelial cell (EC) is known to facilitate transmigration, but the cellular and molecular mechanisms are not well understood.We found that docking structure formation involves the localization and activation of Arp2/3 complex by WAVE2.Finally, we found that ECs in resting endothelial monolayers use lamellipodial protrusions dependent on WAVE2 to form and maintain contacts and junctions between cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Physiology, Washington University, St. Louis, MO 63110.

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Related in: MedlinePlus

WAVE2 and Arp2/3 complex are important for docking structure formation. (A) Frames from Supplemental Movie S1 show a lymphocyte undergoing transcellular transmigration through an EC expressing membrane-tagged GFP. Scale bar, 10 μm. (B) WAVE2, Arp2/3 complex, and F-actin colocalize with rings of ICAM-1 that form around anti–ICAM-1–coated beads in contact with ECs after 30 min of incubation. The yz- and xz-projections from three-dimensional (3D) data sets reveal membrane protrusions extending upward to cup the beads. Scale bar, 20 μm. (C) WAVE2 depletion decreases the number of bead-associated rings stained for F-actin and Arp2/3 complex. Red arrows indicate rings of F-actin and Arp2/3 complex around anti-ICAM-1 beads. Scale bar, 50 μm. (D) WAVE2 depletion decreases the number of beads with associated rings of F-actin and Arp2/3 complex. Beads and positive-stained rings were counted in 10 fov for three separate experiments (N = 30). Box-and-whisker plots show median, interquartile range, and extremes.
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Figure 1: WAVE2 and Arp2/3 complex are important for docking structure formation. (A) Frames from Supplemental Movie S1 show a lymphocyte undergoing transcellular transmigration through an EC expressing membrane-tagged GFP. Scale bar, 10 μm. (B) WAVE2, Arp2/3 complex, and F-actin colocalize with rings of ICAM-1 that form around anti–ICAM-1–coated beads in contact with ECs after 30 min of incubation. The yz- and xz-projections from three-dimensional (3D) data sets reveal membrane protrusions extending upward to cup the beads. Scale bar, 20 μm. (C) WAVE2 depletion decreases the number of bead-associated rings stained for F-actin and Arp2/3 complex. Red arrows indicate rings of F-actin and Arp2/3 complex around anti-ICAM-1 beads. Scale bar, 50 μm. (D) WAVE2 depletion decreases the number of beads with associated rings of F-actin and Arp2/3 complex. Beads and positive-stained rings were counted in 10 fov for three separate experiments (N = 30). Box-and-whisker plots show median, interquartile range, and extremes.

Mentions: To begin TEM, lymphocytes adhere to the endothelial monolayer and walk along its apical surface (Supplemental Movie S1 and Figure 1A). Docking structures form on the EC and bind the lymphocyte, after which the lymphocyte passes through the endothelium via the paracellular or transcellular route. Supplemental Movie S1 and Figure 1A show an example of the latter.


Endothelial cells use dynamic actin to facilitate lymphocyte transendothelial migration and maintain the monolayer barrier.

Mooren OL, Li J, Nawas J, Cooper JA - Mol. Biol. Cell (2014)

WAVE2 and Arp2/3 complex are important for docking structure formation. (A) Frames from Supplemental Movie S1 show a lymphocyte undergoing transcellular transmigration through an EC expressing membrane-tagged GFP. Scale bar, 10 μm. (B) WAVE2, Arp2/3 complex, and F-actin colocalize with rings of ICAM-1 that form around anti–ICAM-1–coated beads in contact with ECs after 30 min of incubation. The yz- and xz-projections from three-dimensional (3D) data sets reveal membrane protrusions extending upward to cup the beads. Scale bar, 20 μm. (C) WAVE2 depletion decreases the number of bead-associated rings stained for F-actin and Arp2/3 complex. Red arrows indicate rings of F-actin and Arp2/3 complex around anti-ICAM-1 beads. Scale bar, 50 μm. (D) WAVE2 depletion decreases the number of beads with associated rings of F-actin and Arp2/3 complex. Beads and positive-stained rings were counted in 10 fov for three separate experiments (N = 30). Box-and-whisker plots show median, interquartile range, and extremes.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Figure 1: WAVE2 and Arp2/3 complex are important for docking structure formation. (A) Frames from Supplemental Movie S1 show a lymphocyte undergoing transcellular transmigration through an EC expressing membrane-tagged GFP. Scale bar, 10 μm. (B) WAVE2, Arp2/3 complex, and F-actin colocalize with rings of ICAM-1 that form around anti–ICAM-1–coated beads in contact with ECs after 30 min of incubation. The yz- and xz-projections from three-dimensional (3D) data sets reveal membrane protrusions extending upward to cup the beads. Scale bar, 20 μm. (C) WAVE2 depletion decreases the number of bead-associated rings stained for F-actin and Arp2/3 complex. Red arrows indicate rings of F-actin and Arp2/3 complex around anti-ICAM-1 beads. Scale bar, 50 μm. (D) WAVE2 depletion decreases the number of beads with associated rings of F-actin and Arp2/3 complex. Beads and positive-stained rings were counted in 10 fov for three separate experiments (N = 30). Box-and-whisker plots show median, interquartile range, and extremes.
Mentions: To begin TEM, lymphocytes adhere to the endothelial monolayer and walk along its apical surface (Supplemental Movie S1 and Figure 1A). Docking structures form on the EC and bind the lymphocyte, after which the lymphocyte passes through the endothelium via the paracellular or transcellular route. Supplemental Movie S1 and Figure 1A show an example of the latter.

Bottom Line: The actin cytoskeleton of the endothelial cell (EC) is known to facilitate transmigration, but the cellular and molecular mechanisms are not well understood.We found that docking structure formation involves the localization and activation of Arp2/3 complex by WAVE2.Finally, we found that ECs in resting endothelial monolayers use lamellipodial protrusions dependent on WAVE2 to form and maintain contacts and junctions between cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Physiology, Washington University, St. Louis, MO 63110.

Show MeSH
Related in: MedlinePlus