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Yang Y, Yamauchi A, Tsuda S, Kuramochi M, Mio K, Sasaki YC, Arai T. The ice-binding site of antifreeze protein irreversibly binds to cell surface for its hypothermic protective function. Biochem Biophys Res Commun 2023; 682:343-348. [PMID: 37837755 DOI: 10.1016/j.bbrc.2023.10.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 10/03/2023] [Indexed: 10/16/2023]
Abstract
Antifreeze proteins (AFPs) are multifunctional polypeptides that adsorb onto ice crystals to inhibit their growth and onto cells to protect them from nonfreezing hypothermic damage. However, the mechanism by which AFP exerts its hypothermic cell protective (HCP) function remains uncertain. Here, we assessed the HCP function of three types of fish-derived AFPs (type I, II, and III AFPs) against human T-lymphoblastic lymphoma by measuring the survival rate (%) of the cells after preservation at 4 °C for 24 h. All AFPs improved the survival rate in a concentration-dependent manner, although the HCP efficiency was inferior for type III AFP compared to other AFPs. In addition, after point mutations were introduced into the ice-binding site (IBS) of a type III AFP, HCP activity was dramatically increased, suggesting that the IBS of AFP is involved in cell adsorption. Significantly, high HCP activity was observed for a mutant that exhibited poorer antifreeze activity, indicating that AFP exerts HCP- and ice-binding functions through a different mechanism. We next incubated the cells in an AFP-containing solution, replaced it with pure EC solution, and then preserved the cells, showing that no significant reduction in the cell survival rate occurred for type I and II AFPs even after replacement. Thus, these AFPs irreversibly bind to the cells at 4 °C, and only tightly adsorbed AFP molecules contribute towards the cell-protection function.
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Affiliation(s)
- Yue Yang
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561, Japan
| | - Akari Yamauchi
- Hibernation Metabolism, Physiology and Development Group, Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan
| | - Sakae Tsuda
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561, Japan; AIST-UTokyo Advanced Operando Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Kashiwa, 277-0882, Japan
| | - Masahiro Kuramochi
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, 316-8511, Japan
| | - Kazuhiro Mio
- AIST-UTokyo Advanced Operando Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Kashiwa, 277-0882, Japan
| | - Yuji C Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561, Japan; AIST-UTokyo Advanced Operando Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Kashiwa, 277-0882, Japan
| | - Tatsuya Arai
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561, Japan; AIST-UTokyo Advanced Operando Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Kashiwa, 277-0882, Japan.
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