Abstract
In the endoplasmic reticulum (ER), newly synthesized subunits of the T-cell antigen receptor (TCR), membrane-bound immunoglobulin (mIg), and major histocompatibility complex (MHC) class I antigens must fold correctly and assemble completely into multimeric protein complexes prior to transport to the cell surface. Although folding and assembly may occur spontaneously, the concept that molecular chaperones facilitate these events is emerging. Here, an intracellular protein of 90-kDa apparent molecular mass, denoted IP90, was shown to be an ER resident protein that associated with partial complexes of the TCR, mIg, and MHC class I proteins but was absent from fully assembled complexes. We speculate that IP90 might participate in folding and assembly processes of these and other multisubunit protein complexes during their transit through the ER.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Antibodies, Monoclonal
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B-Lymphocytes
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Cell Line
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Electrophoresis, Polyacrylamide Gel
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Endoplasmic Reticulum / metabolism*
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Endoplasmic Reticulum / ultrastructure
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Fluorescent Antibody Technique
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Histocompatibility Antigens Class I / isolation & purification
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Histocompatibility Antigens Class I / metabolism*
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Mice
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Microscopy, Immunoelectron
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Molecular Weight
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Proteins / isolation & purification
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Proteins / metabolism*
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Rats
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Receptors, Antigen, B-Cell / isolation & purification
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Receptors, Antigen, B-Cell / metabolism*
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Receptors, Antigen, T-Cell / isolation & purification
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Receptors, Antigen, T-Cell / metabolism*
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T-Lymphocytes
Substances
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Antibodies, Monoclonal
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Histocompatibility Antigens Class I
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Proteins
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Receptors, Antigen, B-Cell
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Receptors, Antigen, T-Cell