Figure 2.

Potential roles of RhoA at the leading edge and uropod during T cell migration. Schematic showing a T cell migrating on the apical surface of EC. In migrating T cells, the microtubule organizing center (MTOC) is behind the nucleus. Boxed areas (blue) highlight RhoA signaling in the lamellipodium (green) and the uropod (red) of the T cell. In the uropod, RhoA is activated by the RhoGEF GEF-H1 and signals through ROCK and p-MLC to induce acto-myosin contraction. In the lamellipodium, we propose that activation of RhoA by as yet unknown RhoGEFs signals via the formin mDIA1 to induce actin polymerization leading to membrane extension, and via ROCK and phosphorylation of myosin light chain (p-MLC) to induce membrane retraction.