CD3G Human, Sf9

CD3G, also known as the T-cell surface glycoprotein CD3 gamma chain, is a protein encoded by the CD3G gene in humans. It is an integral component of the T-cell receptor (TCR) complex, which plays a crucial role in the immune response by recognizing antigens and initiating T-cell activation .

The TCR complex is composed of a variable heterodimer (either TCRαβ or TCRγδ) responsible for ligand recognition and three invariant dimers: CD3γε, CD3δε, and ζζ/CD247. CD3G, specifically, is one of the four peptides (gamma, delta, epsilon, and zeta) that form the CD3 complex . The CD3G chain is essential for the assembly, surface expression, and signaling functions of the TCR complex .

Upon binding of the peptide-MHC complex by the TCR, conformational changes occur in the CD3 complex, leading to the phosphorylation of tyrosine residues within the immunoreceptor tyrosine-based activation motifs (ITAMs) of the cytoplasmic tails of the CD3 and ζζ/CD247 chains. This phosphorylation event triggers a cascade of intracellular signaling pathways that result in T-cell activation and the induction of a cellular immune response .

Mutations in the CD3G gene can lead to immunodeficiencies and autoimmune disorders. Patients with CD3G mutations exhibit T-cell phenotypic and functional defects, particularly in regulatory T cells (Tregs). These defects are characterized by reduced diversity, increased clonality, and impaired suppressive function of Tregs, which contribute to the increased rate of autoimmunity associated with CD3G deficiency .

Recombinant CD3G (Human, Sf9) refers to the CD3G protein produced using the Sf9 insect cell expression system. This system is commonly used for the production of recombinant proteins due to its ability to perform post-translational modifications similar to those in mammalian cells. The recombinant CD3G protein is used in various research applications to study T-cell activation, signaling, and immune responses.