Anti-CD3e

CD3e (CD3-epsilon), together with CD3-gamma, -delta and -zeta, and the T-cell receptor alpha/beta and gamma/delta heterodimers, forms the T-cell receptor-CD3 complex. This complex plays an important role in coupling antigen recognition to several intracellular signal-transduction pathways. The gene for CD3e have been mapped to band q23 of chromosome 11 in humans and consisted of nine exons. Three exons, encoding the junction of leader peptide and mature protein, are extremely small. The CD3e cytoplasmic tail, highly conserved, can be tentatively subdivided into three regions, the N-terminal region contains a basic amino acid cluster, the central region contains a proline-rich sequence, and the C-terminal region contains the ITAM . Among the CD3 subunits, CD3e is the most likely candidate for performing a critical role in the TCR signaling response. CD3e is represented twice in the TCR complex, serving as a component of both the gamma/epsilon and delta/epsilon dimers. In addition, after TCR cross-linking, CD3e and zeta are the predominant tyrosine-phosphorylated TCR subunits. Protein function: Part of the TCR-CD3 complex present on T-lymphocyte cell surface that plays an essential role in adaptive immune response. 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 CD3Z. All CD3 chains contain immunoreceptor tyrosine-based activation motifs (ITAMs) in their cytoplasmic domain. 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:2470098). In addition of this role of signal transduction in T-cell activation, CD3E plays an essential role in correct T-cell development. Initiates the TCR-CD3 complex assembly by forming the two heterodimers CD3D/CD3E and CD3G/CD3E. Participates also in internalization and cell surface down- regulation of TCR-CD3 complexes via endocytosis sequences present in CD3E cytosolic region (PubMed:10384095, PubMed:26507128). [The UniProt Consortium]