Human T-Cell Surface Glycoprotein CD3 Epsilon Chain (CD3E) Protein

Background

CD3E (CD3 epsilon) is one of the key subunits of the T-cell receptor (TCR)-CD3 complex, which is vital for T-cell activation and immune responses. The TCR complex allows T lymphocytes to recognize and respond to antigens presented by major histocompatibility complex (MHC) molecules on antigen-presenting cells (APCs). CD3E plays a critical role in assembling the TCR-CD3 complex and facilitating signal transduction after antigen recognition. The CD3E gene is located on chromosome 11q23 and encodes the CD3ε chain, a type I transmembrane protein essential for the assembly, expression, and signaling function of the TCR. Along with other CD3 subunits (CD3δ, CD3γ, and CD3ζ), CD3E forms part of the signal-transducing complex that transmits signals from the TCR upon antigen engagement. This signal initiates the cascade that leads to T-cell activation, differentiation, and proliferation, all of which are crucial for immune defense against pathogens.