Rap1 translates chemokine signals to integrin activation, cell polarization, and motility across vascular endothelium under flow

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

Rap1 ワ ケモカイン ノ シグナル オ ヘンカンシ インテグリン ノ カッセイカ サイボウ キョクセイ ケイセイ フローカ デノ ケイケッカン ナイヒ ユウソウ オ オコス

京都大学0048新制・課程博士博士(医学)甲第10719号医博第2703号新制||医||857(附属図書館)UT51-2004-G566京都大学大学院医学研究科内科系専攻(主査)教授 成宮 周, 教授 北 徹, 教授 宮地 良樹学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDA