TMX, a human transmembrane oxidoreductase of the thioredoxin family: the possible role in disulfide-linked protein folding in the endoplasmic reticulum
Autor: | Junji Yodoi, Aoi Son, Yumiko Nishinaka, Yasuyuki Ishii, Shingo Suzuki, Norihiko Kondo, Hiroshi Masutani, Shinae Kizaka-Kondoh, Junko Sakakura-Nishiyama, Yoshiyuki Matsuo, Masami Kojima, Yoshimi Yamaguchi |
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Rok vydání: | 2004 |
Předmět: |
Signal peptide
Protein Folding Time Factors animal structures Calnexin Biophysics Protein Sorting Signals Endoplasmic Reticulum Biochemistry Ribonucleases Thioredoxins Humans Protein disulfide-isomerase Molecular Biology Chemistry Endoplasmic reticulum Membrane Proteins Transmembrane protein Organ Specificity Membrane topology Cystine Protein folding Thioredoxin HeLa Cells |
Zdroj: | Archives of Biochemistry and Biophysics. 423:81-87 |
ISSN: | 0003-9861 |
Popis: | Various proteins sharing thioredoxin (Trx)-like active site sequences (Cys-Xxx-Xxx-Cys) have been found and classified in the Trx superfamily. Among them, transmembrane Trx-related protein (TMX) was recently identified as a novel protein possessing an atypical active site sequence, Cys-Pro-Ala-Cys. In the present study, we describe the properties of this membranous Trx-related molecule. Endogenous TMX was detected as a protein of approximately 30 kDa with a cleavable signal peptide. TMX was enriched in membrane fractions and exhibited a similar subcellular distribution with calnexin localized in the endoplasmic reticulum (ER). The examination of membrane topology of TMX suggested that the N-terminal region containing the Trx-like domain was present in the ER lumen, where protein disulfide isomerase (PDI) was found to assist protein folding. Recombinant TMX showed PDI-like activity to refold scrambled RNase. These results indicate the possibility that TMX can modify certain molecules with its oxidoreductase activity and be involved in the redox regulation in the ER. |
Databáze: | OpenAIRE |
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