A unique Ca2+-inhibited C-type lectin in shrimp Fenneropenaeuschinensis

Yajin Xu; Haoran Yang; Jingjie Hu; Zhenmin Bao; Mengqiang Wang

doi:10.1016/j.fsi.2024.109638

A unique Ca²⁺-inhibited C-type lectin in shrimp Fenneropenaeuschinensis

Fish Shellfish Immunol. 2024 May 15:150:109638. doi: 10.1016/j.fsi.2024.109638. Online ahead of print.

Authors

Yajin Xu¹, Haoran Yang¹, Jingjie Hu², Zhenmin Bao¹, Mengqiang Wang³

Affiliations

¹ Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China; MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China; Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya, 572024, China.
² Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China; MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China; Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya, 572024, China. Electronic address: hujingjie@ouc.edu.cn.
³ Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China; MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China; Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya, 572024, China. Electronic address: wangmengqiang@ouc.edu.cn.

PMID: 38754650
DOI: 10.1016/j.fsi.2024.109638

Abstract

C-type lectins (CTLs) are glycan-binding pattern recognition receptors (PRRs) that can bind to carbohydrates on pathogen surfaces, triggering immune responses in shrimp innate immunity. In this study, a unique Ca²⁺-inhibited CTL named FcLec was identified and characterized in Chinese shrimp Fenneropenaeus chinensis. The full-length cDNA sequence of FcLec was 976 bp (GenBank accession number KU361826), with a 615 bp open reading frame (ORF) encoding 204 amino acids. FcLec possesses a C-type lectin-like domain (CTLD) containing four conserved cysteines (Cys105, Cys174, Cys192, and Cys200) and two sugar-binding site structures (QPD and LNP). The tertiary structure of FcLec deduced revealed three α-helices and eight β-pleated sheets. The mRNA expression levels of FcLec in hemocytes and the hepatopancreas were markedly elevated after stimulation with Vibrio anguillarum and white spot syndrome virus (WSSV). The recombinant FcLec protein exhibited Ca²⁺-independent hemagglutination and bacterial agglutination, but these activities were observed only in the presence of EDTA to chelate metal ions. These findings suggest that FcLec plays important and functionally distinct roles in the shrimp's innate immune response to bacteria and viruses, enriching the current understanding of the relationship between CTL activity and Ca²⁺ in invertebrates.

Keywords: C-type lectin; Fenneropenaeus chinensis; Innate immunity; Pattern recognition receptors.