Transport and secretion of truncated T cell receptor beta-chain occurs in the absence of association with CD3.
The T cell receptor (TCR) beta-chain is produced in the endoplasmic reticulum where it associates with the TCR alpha-chain and the members of the CD3 complex to form the complete receptor. When the other chains of the complex are not available, the beta-chain is rapidly degraded within the endoplasmic reticulum. When incomplete TCR.CD3 complexes are formed, they are transported through the Golgi apparatus and degraded in lysosomes. In this study, a truncated form of the TCR beta-chain has been made by removal of the transmembrane and cytoplasmic segments. Unlike the normal beta-chain, the truncated molecule is stable and is transported through the Golgi apparatus and secreted. This process occurs at a similar rate in both T and B cells, indicating that it is not affected by the presence or absence of CD3 components. These data suggest that an element in the transmembrane or cytoplasmic region of the beta-chain confers sensitivity to the degradative control mechanisms that regulate TCR expression.
Gascoigne
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Department of Immunology, Research Institute of Scripps Clinic, La Jolla, California 92037.
D000118:Acetylglucosaminidase / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism*; D001402:B-Lymphocytes / Q000378:metabolism / Q000648:ultrastructure; D001483:Base Sequence; D001692:Biological Transport; D017252:CD3 Complex; D003001:Cloning, Molecular; D004721:Endoplasmic Reticulum; D015870:Gene Expression; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism; D007163:Immunosorbent Techniques; D046911:Macromolecular Substances; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D013601:T-Lymphocytes / Q000378:metabolism / Q000648:ultrastructure; D014162:Transfection; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell; D000118:Acetylglucosaminidase; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase