Mini Review ARTICLE
Tetraspanin CD9: a key regulator of cell adhesion in the immune system
- 1Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Spain
- 2Departamento Inmunología, Oftalmología y OTR, Facultad de Medicina, Universidad Complutense de Madrid, Spain
The tetraspanin CD9 is expressed by all the major subsets of leukocytes (B cells, CD4+ T cells, CD8+ T cells, NK cells, granulocytes, monocytes and macrophages, immature and mature DCs) and also at a high level by endothelial cells. As a typical member of the tetraspanin superfamily, a prominent feature of CD9 is its propensity to engage in a multitude of interactions with other tetraspanins as well as with different transmembrane and intracellular proteins within the context of defined membranal domains termed tetraspanin-enriched domains (TEMs). Through these associations, CD9 influences many cellular activities in the different subtypes of leukocytes and in endothelial cells, including intracellular signaling, proliferation, activation, survival, migration, invasion, adhesion and diapedesis. Several excellent reviews have already covered the topic of how tetraspanins, including CD9, regulate these cellular processes in the different cells of the immune system. In this mini-review, however, we will focus particularly on describing and discussing the regulatory effects exerted by CD9 on different adhesion molecules that play pivotal roles in the physiology of leukocytes and endothelial cells, with a particular emphasis in the regulation of adhesion molecules of the integrin and immunoglobulin superfamilies.
Keywords: CD9, Tetraspanins, Integrins, Cell Adhesion, Immunoglobulin superfamily, immune synapse, Endothelial Cells, ICAM1, ALCAM, ADAM17, LFA-1, VLA-4
Received: 13 Feb 2018;
Accepted: 09 Apr 2018.
Edited by:Manfred B. Lutz, Universität Würzburg, Germany
Reviewed by:Hsi-Hsien Lin, Chang Gung University, Taiwan
José Mordoh, Leloir Institute Foundation (FIL), Argentina
Copyright: © 2018 Cabañas, Reyes, Cardeñes and Machado-Pineda. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Carlos Cabañas, Consejo Superior de Investigaciones Científicas (CSIC), Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, 28049, Spain, firstname.lastname@example.org