Human Cluster of Differentiation 3d (CD3D) Protein

Background

CD3D, the delta subunit of the T-cell receptor (TCR) complex, plays a critical role in T-cell development and activation, which are essential components of the adaptive immune system. The TCR complex is responsible for recognizing antigens presented by major histocompatibility complex (MHC) molecules on the surface of antigen-presenting cells (APCs), allowing T-cells to initiate immune responses against pathogens. The CD3D subunit, along with other CD3 subunits (CD3E, CD3G, and CD3Z), functions as part of the CD3 complex, which couples with the TCR α/β heterodimer to mediate signal transduction following antigen recognition. The CD3D gene, located on chromosome 11q23, encodes the CD3δ chain, a 20-25 kDa protein essential for the assembly and function of the TCR complex. The CD3 complex, including the CD3D subunit, is expressed in all T lymphocytes and plays a vital role in transmitting signals from the extracellular environment to the interior of the cell, initiating downstream signaling cascades essential for T-cell activation, differentiation, and survival.