Protein disulfide isomerase associates with misfolded human lysozyme in vivo.
Wild-type human lysozyme (hLZM) is quantitatively secreted into the media when expressed in mouse fibroblast cells, but some misfolded hLZMs are retained and rapidly degraded in a pre-Golgi compartment (Omura, F., Otsu, M., Yoshimori, T., Tashiro, Y., and Kikuchi, M. (1992) Eur. J. Biochem. 210, 591-599). To detect the association with misfolded hLZMs of cellular proteins involved in their folding, retention, and pre-Golgi degradation, a co-precipitation experiment was carried out using anti-hLZM antibody and metabolically labeled cell lysates, which were treated with a membrane-permeable cross-linking reagent. Here we report that protein disulfide isomerase associated in vivo with misfolded hLZMs, but not with the wild-type protein, and discuss the possible role of protein disulfide isomerase in the quality control of newly synthesized proteins in the endoplasmic reticulum.
Otsu
M
M
Protein Engineering Research Institute, Osaka, Japan.
Omura
F
F
Yoshimori
T
T
Kikuchi
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D006801:Humans; D007535:Isomerases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D007739:L Cells; D051379:Mice; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D011485:Protein Binding; D019704:Protein Disulfide-Isomerases; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D014162:Transfection
D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D009113:Muramidase; D007535:Isomerases; D019704:Protein Disulfide-Isomerases