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Updated: May 29, 2026

Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes
Published on: June 13, 2014
Rap1 and integrin inside-out signaling
Koko Katagiri1, Tatsuo Kinashi
1Department of Life Science, School of Science and Technology, Kansei Gakuin University, Hyogo, Japan. kinashi@takii.kmu.ac.jp
Abstract:
In leukocytes, integrins play important roles in adhesive interactions with endothelium, antigen-presenting cells, and effector functions such as cytotoxicity. This chapter describes methods to study Ras proximity 1 (Rap1), a signaling molecule that has been increasingly recognized as an important regulator of integrin-mediated cell adhesion in the immune system as well as hemostasis. Rap1 is activated by a wide variety of external stimuli including chemokines and antigens. Signaling via Rap1 transmits an inside-out signal to the integrins, thereby increasing adhesiveness to ligands such as immunoglobulin superfamily proteins as well as extracellular matrix proteins and plasma proteins. This process induces leukocyte cell adhesion to the endothelium and antigen-presenting cells. In addition to integrin regulation, activated Rap1 induces cell polarity of lymphocytes, which is coordinated with LFA-1 redistribution to the leading edge.
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