title: Crammed signaling motifs in the T-cell receptor.
abstract: Although the T cell antigen receptor (TCR) is long known to contain multiple signaling subunits (CD3γ, CD3δ, CD3ɛ and CD3ζ), their role in signal transduction is still not well understood. The presence of at least one immunoreceptor tyrosine-based activation motif (ITAM) in each CD3 subunit has led to the idea that the multiplication of such elements essentially serves to amplify signals. However, the evolutionary conservation of non-ITAM sequences suggests that each CD3 subunit is likely to have specific non-redundant roles at some stage of development or in mature T cell function. The CD3ɛ subunit is paradigmatic because in a relatively short cytoplasmic sequence (∼55 amino acids) it contains several docking sites for proteins involved in intracellular trafficking and signaling, proteins whose relevance in T cell activation is slowly starting to be revealed. In this review we will summarize our current knowledge on the signaling effectors that bind directly to the TCR and we will propose a hierarchy in their response to TCR triggering.
authors.affiliation: TCR Signal Transduction Laboratory, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain.
authors.forename: Aldo
authors.initials: A
authors.lastname: Borroto
authors.affiliation: Bioinformatics Unit, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Abia
authors.affiliation: TCR Signal Transduction Laboratory, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain. Electronic address: balarcon@cbm.uam.es.
authors.forename: Balbino
authors.initials: B
authors.lastname: Alarcón
mesh_terms: D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism; D006801:Humans; D061625:Immunoreceptor Tyrosine-Based Activation Motif; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: C441388:CD3 epsilon, wallaby; D002352:Carrier Proteins; D011948:Receptors, Antigen, T-Cell
keywords: CD3epsilon; TCR signaling