The atypical MAPK ERK3 controls positive selection of thymocytes. Issue 1 (May 2015)

• Record Type: Journal Article
• Authors: Sirois, Julien; Daudelin, Jean‐François; Boulet, Salix; Marquis, Miriam; Meloche, Sylvain; Labrecque, Nathalie
• Is Part Of: Immunology. Volume 145:Issue 1(2015:May)
• Page Start: 161
• Page End: 169
• Publication Date: 2015-05
• Subjects: Immunology -- Periodicals
• DOI: 10.1111/imm.12433
• Languages: English
• ISSNs: 0019-2805

Abstract

<abstract abstract-type="main" id="imm12433-abs-0001"> <title>Summary</title> <p>Extracellular signal‐regulated kinase 3 (ERK3 )is an atypical member of the mitogen‐activated protein kinase (MAPK) family. We have previously shown that ERK3 is expressed during thymocyte differentiation and that its expression is induced in mature peripheral T cells following activation of ERK1/2 by T‐cell receptor (TCR) signalling. Herein, we have investigated whether ERK3 expression is required for proper T‐cell selection. Using a knock‐in mouse model in which the coding sequence of ERK3 is replaced by the gene encoding for the <italic>β</italic>‐galactosidase reporter, we show that ERK3 is expressed by double‐positive (DP) thymocytes undergoing positive selection. In ERK3‐deficient mice with a polyclonal TCR repertoire, we observe a decrease in positive selection. This reduction in positive selection was also observed when ERK3‐deficient mice were backcrossed to class I‐ and class II‐restricted TCR transgenic mice. Furthermore, the response of DP thymocytes to <italic>in vitro </italic>TCR stimulation was strongly reduced in ERK3‐deficient mice. Together, these results show that ERK3 expression following TCR signalling is critical for proper thymic positive selection.</p> </abstract>