Recombinant Mouse T-cell surface glycoprotein CD3 epsilon chain (Cd3e), partial

Function

Part of the TCR-CD3 complex present on T-lymphocyte cell surface that plays an essential role in adaptive immune response (PubMed:9843989, PubMed:10952314, PubMed:19956738, PubMed:24470497, PubMed:24899501, PubMed:40592325). When antigen presenting cells (APCs) activate T-cell receptor (TCR), TCR-mediated signals are transmitted across the cell membrane by the CD3 chains CD3D, CD3E, CD3G and CD247/CD3Z (PubMed:10952314, PubMed:19956738, PubMed:24899501, PubMed:40592325). All CD3 chains contain immunoreceptor tyrosine-based activation motifs (ITAMs) in their cytoplasmic domain (PubMed:10952314, PubMed:19956738, PubMed:24899501, PubMed:40592325). Upon TCR engagement, these motifs become phosphorylated by Src family protein tyrosine kinases LCK and FYN, resulting in the activation of downstream signaling pathways (PubMed:10952314, PubMed:19956738, PubMed:24899501, PubMed:40592325). CD3E ITAM phosphorylation creates docking sites for the protein kinase ZAP70 leading to ZAP70 phosphorylation and its conversion into a catalytically active enzyme (PubMed:10952314). In addition of this role of signal transduction in T-cell activation, CD3E plays an essential role in correct T-cell development (PubMed:10952314, PubMed:19956738, PubMed:24899501). Also participates in internalization and cell surface down-regulation of TCR-CD3 complexes via endocytosis sequences present in CD3E cytosolic region (By similarity). In addition to its role as a TCR coreceptor, it serves as a receptor for ITPRIPL1 (By similarity). Ligand recognition inhibits T-cell activation by promoting interaction with NCK1, which prevents CD3E-ZAP70 interaction and blocks the ERK-NFkB signaling cascade and calcium influx (By similarity)

Subcellular Location

Cell membrane (Single-pass type I membrane protein)

Subunit

The TCR-CD3 complex is composed of a CD3D-CD3E and a CD3G-CD3E heterodimers that preferentially associate with TCRalpha and TCRbeta, respectively, to form TCRalpha-CD3E-CD3G and TCRbeta/CD3G-CD3E trimers (PubMed:40592325). In turn, the hexamer interacts with CD247/CD3Z homodimer to form the TCR-CD3 complex (By similarity). Alternatively, TCRalpha and TCRbeta can be replaced by TCRgamma and TCRdelta (By similarity). Interacts with CD6 (By similarity). Interacts (via Proline-rich sequence) with NCK1; the interaction is ligand dependent but independent of tyrosine kinase activation (PubMed:24470497). Interacts (when tyrosine phosphorylated) with LAG3; disrupting the association between CD3E and LCK and preventing TCR activation (By similarity)

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