Externalization and recognition by macrophages of large subunit of eukaryotic translation initiation factor 3 in apoptotic cells
- Graduate School of Natural Science and Technology, Kanazawa University, Shizenken, Kakuma-machi, Kanazawa, Ishikawa 920-1192 (Japan)
- Graduate School of Medical Science, Kanazawa University, Shizenken, Kakuma-machi, Kanazawa, Ishikawa 920-1192 (Japan)
- Advanced Development and Supporting Center, RIKEN, Hirosawa, Wako, Saitama 351-0198 (Japan)
- Highthroughput Factory, RIKEN Harima Institute, Mikazuki, Sayo, Hyogo 679-5148 (Japan)
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Walnut Street, Indianapolis, Indiana 46202 (United States)
- Department of Anatomy, the University of Miyazaki, Kiyotake-cho, Miyazaki 889-1692 (Japan)
- Graduate School of Natural Science and Technology, Kanazawa University, Shizenken, Kakuma-machi, Kanazawa, Ishikawa 920-1192 (Japan) and Graduate School of Medical Science, Kanazawa University, Shizenken, Kakuma-machi, Kanazawa, Ishikawa 920-1192 (Japan)
We previously isolated a monoclonal antibody named PH2 that inhibits phosphatidylserine-mediated phagocytosis of apoptotic cells by macrophages [C. Fujii, A. Shiratsuchi, J. Manaka, S. Yonehara, Y. Nakanishi. Cell Death Differ. 8 (2001) 1113-1122]. We report here the identification of the cognate antigen. A protein bound by PH2 in Western blotting was identified as the 170-kDa subunit of eukaryotic translation initiation factor 3 (eIF3 p170/eIF3a). When eIF3a was expressed in a culture cell line as a protein fused to green fluorescence protein, the fusion protein was detected at the cell surface only after the induction of apoptosis. The same phenomenon was seen when the localization of endogenous eIF3a was determined using anti-eIF3a antibody, and eIF3a seemed to be partially degraded during apoptosis. Furthermore, bacterially expressed N-terminal half of eIF3a fused to glutathione S-transferase bound to the surface of macrophages and inhibited phagocytosis of apoptotic cells by macrophages when it was added to phagocytosis reactions. These results collectively suggest that eIF3a translocates to the cell surface upon apoptosis, probably after partial degradation, and bridges apoptotic cells and macrophages to enhance phagocytosis.
- OSTI ID:
- 20717654
- Journal Information:
- Experimental Cell Research, Vol. 309, Issue 1; Other Information: DOI: 10.1016/j.yexcr.2005.05.006; PII: S0014-4827(05)00225-9; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0014-4827
- Country of Publication:
- United States
- Language:
- English
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