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Wang J, Wang W, Xu J, Jia Z, Liu Q, Zhu X, Xia C, Zou J. Structural insights into the co-evolution of IL-2 and its private receptor in fish. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 115:103895. [PMID: 33065202 DOI: 10.1016/j.dci.2020.103895] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/11/2020] [Accepted: 10/11/2020] [Indexed: 06/11/2023]
Abstract
Interleukin (IL) -2, a member of the four α-helical cytokine family, has broad regulatory roles in mediating vertebrate immune response. In mammals, IL-2 and IL-15 share a common evolutionary origin and possess overlapping but distinct functions. IL-2 and IL-15 bind to distinct private receptors for signaling. However, fish appear to possess a single IL-15Rα like gene whilst lack additional gene(s) coding for IL-2Rα. Whether the IL-2 and IL-15 interact with the same receptor in fish and how their functions and receptors have evolved are not fully understood. In this study, homologues of IL-2 and IL-2/15Rα were sequenced from a teleost species, grass carp (Ctenopharyngodon idella), and the crystal structure of IL-2 was determined. The grass carp IL-2 (termed CiIL-2) displayed a classical cytokine structure consisting of four helical bundles which shares significant similarity with human IL-15. The key amino acids involved in the interface interaction of IL-2/15 and their receptors are well conserved. The CiIL-2 has been shown to bind the IL-2/15Rα like homologue with an affinity of 2.45 nM, supporting the notion that fish IL-2 and IL-15 may share a single common private receptor for exerting functions. Syntenic analysis suggests that the IL-2Rα of tetrapods has evolved from an IL-15Rα like homologue, in which a second sushi domain (D2) in the extracellular region has been duplicated to facilitate the specific interaction with IL-2. The CiIL-2 was predominantly expressed in lymphocyte-rich tissues such as the spleen, kidney and thymus, and could be induced by PHA and IL-21. In vivo challenge with grass carp reovirus and Flavobacterium columnare also resulted in upregulation of CiIL-2 expression. The recombinant CiIL-2 was shown to activate expression of STAT5b, IL-1β, IL-22 and IFN-γ, and to promote the proliferation of the primary cell cultures from head kidney leucocytes. Our results shed lights into the co-evolution of IL-2 and its private receptor, and the functional divergence of IL-2 and IL-15 during evolution.
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Affiliation(s)
- Junya Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; Department of Microbiology and Immunology, College of Veterinary Medicine, China Agricultural University, Haidian District, Beijing, 100094, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Wei Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Jiawen Xu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Zhao Jia
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Qin Liu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Xiaozhen Zhu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Chun Xia
- Department of Microbiology and Immunology, College of Veterinary Medicine, China Agricultural University, Haidian District, Beijing, 100094, China.
| | - Jun Zou
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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Newman J, Sharp JA, Enjapoori AK, Bentley J, Nicholas KR, Adams TE, Peat TS. Structural characterization of a novel monotreme-specific protein with antimicrobial activity from the milk of the platypus. Acta Crystallogr F Struct Biol Commun 2018; 74:39-45. [PMID: 29372906 PMCID: PMC5947691 DOI: 10.1107/s2053230x17017708] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 12/12/2017] [Indexed: 11/10/2022] Open
Abstract
Monotreme lactation protein (MLP) is a recently identified protein with antimicrobial activity. It is present in the milk of monotremes and is unique to this lineage. To characterize MLP and to gain insight into the potential role of this protein in the evolution of lactation, the crystal structure of duck-billed platypus (Ornithorhynchus anatinus) MLP was determined at 1.82 Å resolution. This is the first structure to be reported for this novel, mammalian antibacterial protein. MLP was expressed as a FLAG epitope-tagged protein in mammalian cells and crystallized readily, with at least three space groups being observed (P1, C2 and P21). A 1.82 Å resolution native data set was collected from a crystal in space group P1, with unit-cell parameters a = 51.2, b = 59.7, c = 63.1 Å, α = 80.15, β = 82.98, γ = 89.27°. The structure was solved by SAD phasing using a protein crystal derivatized with mercury in space group C2, with unit-cell parameters a = 92.7, b = 73.2, c = 56.5 Å, β = 90.28°. MLP comprises a monomer of 12 helices and two short β-strands, with much of the N-terminus composed of loop regions. The crystal structure of MLP reveals no three-dimensional similarity to any known structures and reveals a heretofore unseen fold, supporting the idea that monotremes may be a rich source for the identification of novel proteins. It is hypothesized that MLP in monotreme milk has evolved to specifically support the unusual lactation strategy of this lineage and may have played a central role in the evolution of these mammals.
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Affiliation(s)
- Janet Newman
- Biomedical Manufacturing, CSIRO, 343 Royal Parade, Parkville, VIC 3052, Australia
| | - Julie A. Sharp
- Institute for Frontier Materials, Deakin University, Geelong, VIC 3217, Australia
| | | | - John Bentley
- Biomedical Manufacturing, CSIRO, 343 Royal Parade, Parkville, VIC 3052, Australia
| | - Kevin R. Nicholas
- Institute for Frontier Materials, Deakin University, Geelong, VIC 3217, Australia
| | - Timothy E. Adams
- Biomedical Manufacturing, CSIRO, 343 Royal Parade, Parkville, VIC 3052, Australia
| | - Thomas S. Peat
- Biomedical Manufacturing, CSIRO, 343 Royal Parade, Parkville, VIC 3052, Australia
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