Koning F, Maloy W L, Coligan J E
Department of Immunohematology, University Hospital, Leiden, The Netherlands.
Eur J Immunol. 1990 Feb;20(2):299-305. doi: 10.1002/eji.1830200211.
Cell surface-expressed receptors are often multichain complexes. One of these, the T cell receptor (TcR) alpha/beta-CD3 complex, is known to contain at least seven chains: the alpha and beta TcR chains plus the gamma, delta, epsilon and two zeta chains from the CD3 complex (alpha beta gamma delta epsilon zeta 2). To gain insight into the structure of the complex we have used anti-peptide antisera specific for the individual subunits of the complex, and nonionic and ionic detergents to determine subunit interactions within the complex. Four closely associated pairs of chains could be identified: alpha beta, zeta 2, gamma epsilon and delta epsilon. Interactions between the TcR alpha beta and either gamma epsilon or delta epsilon could be observed in the apparent absence of other CD3 chains. Furthermore, a hierarchy in the strength of the association between the TcR and the individual CD3 chains could be distinguished: TcR epsilon greater than TcR delta greater than TcR gamma. The zeta 2 dimer could only be detected in "intact" TcR-CD3 complexes shedding no light on possible interactions with either the TcR or CD3-gamma, delta and epsilon chains. Finally, cross-linking experiments suggest a close spatial relationship between the TcR alpha beta and both the CD3-gamma and CD3-epsilon chains. The results demonstrate that the methods used give valuable information on subunit interactions in a cell surface-expressed receptor complex and suggest a TcR-CD3 complex in which two epsilon chains are present, one linked to gamma and the other to delta. The data further indicate that gamma epsilon and delta epsilon complexes interact directly with the TcR chains. Based on the observations a model for the structure of the TcR-CD3 is presented and discussed.
细胞表面表达的受体通常是多链复合物。其中之一，即T细胞受体（TcR）α/β - CD3复合物，已知至少包含七条链：α和β TcR链加上来自CD3复合物的γ、δ、ε和两条ζ链（αβγδεζ₂）。为深入了解该复合物的结构，我们使用了对复合物各个亚基具有特异性的抗肽抗血清，以及非离子和离子去污剂来确定复合物内亚基之间的相互作用。可以识别出四对紧密相关的链：αβ、ζ₂、γε和δε。在明显不存在其他CD3链的情况下，可以观察到TcRαβ与γε或δε之间的相互作用。此外，可以区分出TcR与各个CD3链之间结合强度的层次结构：TcR ε大于TcR δ大于TcR γ。ζ₂二聚体只能在“完整”的TcR - CD3复合物中检测到，这对于其与TcR或CD3 - γ、δ和ε链之间可能的相互作用没有提供线索。最后，交联实验表明TcRαβ与CD3 - γ和CD3 - ε链之间存在紧密的空间关系。结果表明，所使用的方法为细胞表面表达的受体复合物中的亚基相互作用提供了有价值的信息，并提示存在一种TcR - CD3复合物，其中存在两条ε链，一条与γ相连，另一条与δ相连。数据进一步表明γε和δε复合物直接与TcR链相互作用。基于这些观察结果，提出并讨论了TcR - CD3的结构模型。
