Purification, microsequencing, and immunolocalization of p36, a new interferon-alpha-induced protein that is associated with human lupus inclusions.
The trace interferon-alpha-induced protein, p36, was induced in Raji cells in association with lupus inclusions. It was solubilized in a nonionic detergent buffer, enriched by differential centrifugation and by preparative isoelectric focusing, and purified to homogeneity on two-dimensional protein gels. Failure to obtain N-terminal amino acid sequence, however, suggested a blocked alpha-amino group. Sequences of six tryptic peptides, 13-19 amino acids in length, were obtained after digestion, microbore-high performance liquid chromotography purification, and chemical sequence analysis. None of the six sequences, which represented approximately 25% of the entire protein, shared any meaningful homologies with entries in protein sequence repositories. Raji-cell p36 was shown in Western blots with antipeptide antibodies to be induced at least 400-fold and by immunofluorescence microscopy to co-localize with the endoplasmic reticulum resident protein, protein disulfide isomerase. These results show that p36 is a new interferon-alpha-induced protein that localizes in the endoplasmic reticulum, the cell region in which the lupus inclusions form, and that p36 is probably physically associated with the lupus inclusions.
Rich
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SA
Laboratory of Cell Regulation, Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201-0509, USA.
Bose
M
M
Tempst
P
P
Rudofsky
U H
UH
D000595:Amino Acid Sequence; D017306:Annexin A2 / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification*; D001402:B-Lymphocytes / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D002851:Chromatography, High Pressure Liquid; D003594:Cytoplasmic Granules / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D008177:Lupus Vulgaris / Q000378:metabolism*; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D008970:Molecular Weight; D014407:Tumor Cells, Cultured
D017306:Annexin A2; D016898:Interferon-alpha