C-type lectin with a QPN motif from swimming crab Portunus trituberculatus displays broad nonself-recognition ability and functions as an opsonin. (July 2021)

• Record Type: Journal Article
• Authors: Kang, Ting; Xia, Yanting; Dong, Taiwei; Zheng, Xiaoyuan; Yang, Shun; Qian, Shichao; Huang, Mengmeng; Fei, Hui
• Is Part Of: Developmental and comparative immunology. Volume 120(2021)
• Publication Date: 2021-07
• Subjects: Portunus trituberculatus -- Innate immunity -- C-type lectin -- Nonself-recognition -- Encapsulation; Immunology -- Periodicals; Developmental immunology -- Periodicals; 616.079
• DOI: 10.1016/j.dci.2021.104066
• Languages: English
• ISSNs: 0145-305X

Abstract

Abstract: In the immune system, C-type lectins, as pattern recognition receptors, have an important function. Carbohydrate-recognition domains (CRDs) endow C-type lectins with the function of recognizing and scavenging non-self factors. In the present study, a new C-type lectin (designated as PtCTL-9 according to the order of discovery) from swimming crab ( Portunus trituberculatus ) was characterized. QPN (Gln-Pro-Asn) and FHS (Phe-His-Ser) were identified as the key motifs that determine carbohydrate binding. Motif QPN was mutated to QPD (Gln-Pro-Asp) (M1) and EPN (Glu-Pro-Asn) (M2) to study its immune function and for comparative analysis. The results showed that PtCTL-9 displayed broad non-self immunity. PtCTL-9 could also function as an opsonin to promote phagocytosis and the in vitro encapsulation of hemocytes. These results indicated that PtCTL-9 has an extensive nonself-recognition ability, regulates pathogen clearance, and its QPN motif is important in PtCTL-9's immune function. Highlights: A C-type lectin PtCTL-9 with a novel QPN motif was identified from Portunus trituberculatus. PtCTL-9 possessed strong binding activity to nonself particles while its two mutants displayed weak binding activity. PtCTL-9 inhibited the growth of S. cerevisiae. PtCTL-9 promoted phagocytosis and encapsulation activity of hemocytes in vitro.