CD3 zeta/CD247 Protein, Human (His)

CD3 zeta/CD247, an integral component of the TCR-CD3 complex on the T-lymphocyte cell surface, plays a crucial role in adaptive immune responses. When activated by antigen-presenting cells (APCs), the T-cell receptor (TCR)-mediated signals are transmitted across the cell membrane through CD3 chains, including CD3D, CD3E, CD3G, and CD3Z. These chains contain immunoreceptor tyrosine-based activation motifs (ITAMs) in their cytoplasmic domain, which, upon TCR engagement, become phosphorylated by Src family protein tyrosine kinases LCK and FYN. The phosphorylation of CD3Z ITAMs creates multiple docking sites for the protein kinase ZAP70, leading to ZAP70 phosphorylation and its conversion into a catalytically active enzyme. Beyond its role in signal transduction, CD3Z is essential for intrathymic T-cell differentiation and contributes to the activity-dependent synapse formation of retinal ganglion cells (RGCs) in the retina and dorsal lateral geniculate nucleus (dLGN). The TCR-CD3 complex, comprising heterodimers CD3D/CD3E and CD3G/CD3E, associates preferentially with TCRalpha and TCRbeta, forming trimers. The hexamer interacts with CD3Z homodimers to complete the TCR-CD3 complex, demonstrating its versatility in TCR assembly. Additionally, CD3Z interacts with various proteins, such as SLA, TRAT1, DOCK2, SHB, ZAP70, and others, contributing to its multifaceted functions in immune responses and cellular interactions.