부산대학교 도서관

Pairwise assembly of human CD3 chains takes place in the endoplasmic reticulum of T cells. Subsequently, the CD3 heterodimers form complexes with Tiα and Tiß chains forming hexameric TiαβCD3γεδε complexes. Finally, association with the ζ2 homodimer occurs in Golgi apparatus before the fully assembled T-cell receptor is transported to the cell surface. To study the structural properties of the human CD3 chains, we have developed new methods to produce and fold the extracellular domains of CD3γ, CD3δ and CD3ε. Proteins were expressed in Escherichia coli as denatured chains and de novo folded in vitro . CD3γ and CD3ε folded as soluble monomers, whereas CD3δ did not yield any soluble proteins. When folding the chains pairwise, soluble CD3γε and CD3δε heterodimers could be isolated, whereas CD3γδ heterodimers were not produced. Using antibodies as structural probes, we identified two different types of antigenic epitopes that were dependent on heterodimerization. Our data indicate that CD3ε undergoes a conformational change after dimerization with CD3γ or CD3δ. Furthermore, we demonstrated that the CD3γε heterodimer could be purified using immunoaffinity chromatography. [ABSTRACT FROM AUTHOR]