Gaëtan Blaize, Hélène Daniels-Treffandier, Meryem Aloulou, Nelly Rouquié, Cui Yang, Marlène Marcellin, Mylène Gador, Mehdi Benamar, Mariette Ducatez, Ki-Duk Song, Odile Burlet-Schiltz, Abdelhadi Saoudi, Paul E Love, Nicolas Fazilleau, Anne Gonzalez de Peredo, Renaud Lesourne
CD5 is characterized as an inhibitory coreceptor with an important regulatory role during T cell development. The molecular mechanism by which CD5 operates has been puzzling and its function in mature T cells suggests promoting rather than repressing effects on immune responses. Here, we combined quantitative mass spectrometry and genetic studies to analyze the components and the activity of the CD5 signaling machinery in primary T cells. We found that T cell receptor (TCR) engagement induces the selective phosphorylation of CD5 tyrosine 429, which serves as a docking site for proteins with adaptor functions (c-Cbl, CIN85, CRKL), connecting CD5 to positive (PI3K) and negative (UBASH3A, SHIP1) regulators of TCR signaling...
May 20, 2020: Proceedings of the National Academy of Sciences of the United States of America