Endothelial cells use dynamic actin to facilitate lymphocyte transendothelial migration and maintain the monolayer barrier.
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.
Affiliation: Department of Cell Biology and Physiology, Washington University, St. Louis, MO 63110.Show MeSH
Related in: MedlinePlus
Mentions: For the paracellular route, PBLs migrated over the course of 2–5 min through a pore that formed between two ECs. The pore often remained open for several minutes after the PBL moved away from the transmigration site (Figure 2A; asterisk indicates a persisting pore). WAVE2-GFP did not accumulate at the transmigration site either before or during transmigration (Figure 2A and Supplemental Movie S2). When the pores closed, if the pore size was large, ECs produced waves of membrane protrusion as they closed the gap. WAVE2-GFP localized at the front of these protrusions, which traveled laterally along the edge of the EC (Figure 2B and Supplemental Movie S3). This dynamic behavior is consistent with the idea that WAVE2 activates Arp2/3 complex and promotes actin assembly to drive the formation and extension of membrane protrusions. Small pores sometimes closed rapidly, without membrane protrusions, and WAVE2-GFP did not accumulate.
Affiliation: Department of Cell Biology and Physiology, Washington University, St. Louis, MO 63110.