Rap1 Translates Chemokine Signals to Integrin Activation, Cell Polarization, and Motility across Vascular Endothelium under Flow

• Published in: The Journal of cell biology Vol. 161; no. 2; pp. 417 - 427
• Main Authors: Shimonaka, Mika, Katagiri, Koko, Nakayama, Toshinori, Fujita, Naoya, Tsuruo, Takashi, Yoshie, Osamu, Kinashi, Tatsuo
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 28.04.2003; The Rockefeller University Press
• Subjects: Adenoviruses; Animals; Blood vessels; Cell Adhesion - drug effects; Cell Adhesion - physiology; Cell Polarity - drug effects; Cell Polarity - physiology; Cells, Cultured; Chemokine CCL21; Chemokine CXCL12; Chemokines; Chemokines - metabolism; Chemokines, CC - metabolism; Chemokines, CC - pharmacology; Chemokines, CXC - metabolism; Chemokines, CXC - pharmacology; Chemotaxis, Leukocyte - drug effects; Chemotaxis, Leukocyte - physiology; Endothelial cells; Endothelium, Vascular - metabolism; GTPase-Activating Proteins; Hemodynamics - drug effects; Hemodynamics - physiology; Human migration; Hyaluronan Receptors - genetics; Hyaluronan Receptors - metabolism; Integrins; Integrins - metabolism; Intercellular Adhesion Molecule-1 - genetics; Intercellular Adhesion Molecule-1 - metabolism; Leukocytes; Lymphatic system; Lymphocyte Function-Associated Antigen-1 - metabolism; Lymphocytes; Lymphocytes - drug effects; Lymphocytes - metabolism; Mice; Mice, Inbred BALB C; Molecules; Nuclear Proteins - metabolism; Nuclear Proteins - pharmacology; rap1 GTP-Binding Proteins - antagonists & inhibitors; rap1 GTP-Binding Proteins - genetics; rap1 GTP-Binding Proteins - metabolism; Receptors, CXCR4 - genetics; Receptors, CXCR4 - metabolism; Shear stress; Signal Transduction - drug effects; Signal Transduction - physiology; T lymphocytes; Transmigration; Vascular Cell Adhesion Molecule-1 - genetics; Vascular Cell Adhesion Molecule-1 - metabolism
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200301133

Chemokines arrest circulating lymphocytes within the vasculature through the rapid up-regulation of leukocyte integrin adhesive activity, promoting subsequent lymphocyte transmigration. However, the key regulatory molecules regulating this process have remained elusive. Here, we demonstrate that Rap1 plays a pivotal role in chemokine-induced integrin activation and migration. Rap1 was activated by secondary lymphoid tissue chemokine (SLC; CCL21) and stromal-derived factor 1 (CXCL4) treatment in lymphocytes within seconds. Inhibition of Rap1 by Spa1, a Rap1-specific GTPase-activating protein, abrogated chemokine-stimulated lymphocyte rapid adhesion to endothelial cells under flow via intercellular adhesion molecule 1. Expression of a dominant active Rap1V12 in lymphocytes stimulated shear-resistant adhesion, robust cell migration on immobilized intercellular adhesion molecule 1 and vascular cell adhesion molecule 1, and transendothelial migration under flow. We also demonstrated that Rap1V12 expression in lymphocytes induced a polarized morphology, accompanied by the redistribution of CXCR4 and CD44 to the leading edge and uropod, respectively. Spa1 effectively suppressed this polarization after SLC treatment. This unique characteristic of Rap1 may control chemokine-induced lymphocyte extravasation.