1
|
Yang TZ, Zhu Q, Xue T, Cao M, Fu Q, Yang N, Li C, Huo HJ. Identification and functional characterization of CL-11 in black rockfish (Sebastes schlegelii). FISH & SHELLFISH IMMUNOLOGY 2022; 131:527-536. [PMID: 36265742 DOI: 10.1016/j.fsi.2022.10.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/12/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
CL-11 (Collectin-11, also known as Collectin kidney-1 or CL-K1) is a member of collectin family that works as a pattern recognition molecule (PRM) and participating in lectin-complement pathway in host defense against pathogens. We identified the CL-11 homologue SsCL-11 in black rockfish (Sebastes schlegelii) and investigated the functional characteristics in this study. The SsCL-11 has conserved protein modules, i.e. an N-terminal hydrophobic region, a collagen-like region, an α-helical neck region and a carbohydrate recognition domain (CRD). SsCL-11 has varying degrees of expressions in difference tissues, among which the highest expression is observed in liver. It also shows induced expressions in immune-related tissues following Aeromonas salmonicida (A. salmonicida) infection. In addition, SsCL-11 exhibits binding abilities to different kinds of carbohydrates, pathogen-associated molecular patterns (PAMPs) and bacteria. It exhibits comparatively strong binding to l-fucose, d-mannose, and d-glucose, which is consistent with the functional EPN motif in its CRD. SsCL-11 also shows agglutinating effects on various bacteria in the presence of Ca2+. Furthermore, SsCL-11 is confirmed to be a secretory lectin and can form multimers. These findings collectively demonstrate that SsCL-11 can function as a recognition molecule in pathogen resistance in black rockfish, which will promote our understanding of immunological roles of fish collectins.
Collapse
Affiliation(s)
- Tian Zhen Yang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Qing Zhu
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Ting Xue
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Min Cao
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Qiang Fu
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Ning Yang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Chao Li
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China.
| | - Hui Jun Huo
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China.
| |
Collapse
|
2
|
The crystal structure of iC3b-CR3 αI reveals a modular recognition of the main opsonin iC3b by the CR3 integrin receptor. Nat Commun 2022; 13:1955. [PMID: 35413960 PMCID: PMC9005620 DOI: 10.1038/s41467-022-29580-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 03/15/2022] [Indexed: 12/27/2022] Open
Abstract
Complement activation on cell surfaces leads to the massive deposition of C3b, iC3b, and C3dg, the main complement opsonins. Recognition of iC3b by complement receptor type 3 (CR3) fosters pathogen opsonophagocytosis by macrophages and the stimulation of adaptive immunity by complement-opsonized antigens. Here, we present the crystallographic structure of the complex between human iC3b and the von Willebrand A inserted domain of the α chain of CR3 (αI). The crystal contains two composite interfaces for CR3 αI, encompassing distinct sets of contiguous macroglobulin (MG) domains on the C3c moiety, MG1-MG2 and MG6-MG7 domains. These composite binding sites define two iC3b-CR3 αI complexes characterized by specific rearrangements of the two semi-independent modules, C3c moiety and TED domain. Furthermore, we show the structure of iC3b in a physiologically-relevant extended conformation. Based on previously available data and novel insights reported herein, we propose an integrative model that reconciles conflicting facts about iC3b structure and function and explains the molecular basis for iC3b selective recognition by CR3 on opsonized surfaces. Complement activation on foreign cell surfaces leads to the generation of complement opsonins, which activate complement receptor type 3 (CR3) and pathogen clearance by macrophages. Here, the authors reveal structural basis of the interaction between human opsonin iC3b and the von Willebrand A inserted domain of the α chain of CR3.
Collapse
|