0000000000067806
AUTHOR
Gerardo R. Vasta
A rhamnose-binding lectin from sea bass (Dicentrarchus labrax) plasma agglutinates and opsonizes pathogenic bacteria
Abstract The discovery of rhamnose-binding lectins (RBLs) in teleost fish eggs led to the identification of a novel lectin family characterized by a unique sequence motif and a structural fold, and initially proposed to modulate fertilization. Further studies of the RBL tissue localization and gene organization were also suggestive of role(s) in innate immunity. Here we describe the purification, and biochemical and functional characterization of a novel RBL (DlRBL) from sea bass (Dicentrarchus labrax) serum. The purified DlRBL had electrophoretic mobilities corresponding to 24 kDa and 100 kDa under reducing and non-reducing conditions, respectively, suggesting that in plasma the DlRBL is p…
Isolation and characterization of a fish F-type lectin from gilt head bream (Sparus aurata) serum.
A novel fucose-binding lectin, designated SauFBP32, was purified by affinity chromatography on fucose-agarose, from the serum of the gilt head bream Sparus aurata. Electrophoretic mobility of the subunit revealed apparent molecular weights of 35 and 30 kDa under reducing and non-reducing conditions, respectively. Size exclusion analysis suggests that the native lectin is a monomer under the selected experimental conditions. Agglutinating activity towards rabbit erythrocytes was not significantly modified by addition of calcium or EDTA; activity was optimal at 37 degrees C, retained partial activity by treatment at 70 degrees C, and was fully inactivated at 90 degrees C. On western blot anal…
Structural and functional diversity of the lectin repertoire in teleost fish: Relevance to innate and adaptive immunity
Protein–carbohydrate interactions mediated by lectins have been recognized as key components of innate immunity in vertebrates and invertebrates, not only for recognition of potential pathogens, but also for participating in downstream effector functions, such as their agglutination, immobilization, and complement-mediated opsonization and killing. More recently, lectins have been identified as critical regulators of mammalian adaptive immune responses. Fish are endowed with virtually all components of the mammalian adaptive immunity, and are equipped with a complex lectin repertoire. In this review, we discuss evidence suggesting that: (a) lectin repertoires in teleost fish are highly dive…
Evolution and Immune Function of Fish Lectins
Abstract Lectins are sugar-binding proteins widely distributed among animals, plants, and microbial taxon, involved in diverse biological processes. In both invertebrates and vertebrates, they play key roles in nonself recognition and immune responses, such as nonself recognition, inflammatory processes, and immunomodulation. In fish, many lectin families have been identified, and their tissue-specific expression and localization of the various lectin repertoires and their ligands are consistent with their distinct biological roles in innate and adaptive immunity. Here, we discuss the involvement of F-type lectins, rhamnose-binding lectins, galectins, and C-type lectins in pathogen recognit…
Evidence of Heavy Methylation in the Galectin 3 Promoter in Early Stages of Prostate Adenocarcinoma: Development and Validation of a Methylated Marker for Early Diagnosis of Prostate Cancer
Galectins, soluble intracellular and extracellular β-galactoside–binding proteins, are known to be involved in the progression and metastasis of various cancers, including prostate adenocarcinoma, but the detailed mechanism of their biological roles remains elusive. In the prostate cancer cell lines PC-3 and DU-145, galectin 3 (gal3) is present at normal levels, whereas in LNCaP, its expression is silenced. In LNCaP, the gal3 promoter was heavily methylated, whereas PC-3 or DU-145 cells showed negligible or no methylation in the gal3 promoter indicating a negative correlation between gal3 promoter methylation and its expression. On immunohistochemical analysis of normal and tumor prostate t…
F-type lectin from the sea bass (Dicentrarchus labrax): purification, cDNA cloning, tissue expression and localization, and opsonic activity.
Recently described biochemical and structural aspects of fucose-binding lectins from the European eel (Anguilla anguilla) and striped bass (Morone saxatilis) led to the identification of a novel lectin family ("F-type" lectins) characterized by a unique sequence motif and a characteristic structural fold. The F-type fold is shared not only with other members of this lectin family, but also with apparently unrelated proteins ranging from prokaryotes to vertebrates. Here we describe the purification, biochemical and molecular properties, and the opsonic activity of an F-type lectin (DlFBL) isolated from sea bass (Dicentrarchus labrax) serum. DlFBL exhibits two tandemly arranged carbohydrate-r…
F-type lectin from serum of the Antarctic teleost fish Trematomus bernacchii (Boulenger, 1902): Purification, structural characterization, and bacterial agglutinating activity.
Abstract The increasing availability of sequenced genomes has enabled a deeper understanding of the complexity of fish lectin repertoires involved in early development and immune recognition. The teleost fucose-type lectin (FTL) family includes proteins that preferentially bind fucose and display tandemly arrayed carbohydrate-recognition domains (CRDs) or are found in mosaic combinations with other domains. They function as opsonins, promoting phagocytosis and the clearance of microbial pathogens. The Antarctic fish Trematomus bernacchii is a Perciforme living at extremely low temperatures (−1.68 °C) which is considered a model for studying adaptability to the variability of environmental w…
Primary structure and opsonic activity of an F-lectin from serum of the gilt head breamSparus aurata(Pisces, Sparidae)
Abstract The recently described fucose-binding agglutinin from the European eel revealed a novel lectin fold (the ‘F-type’ fold) that is shared with other carbohydrate-binding proteins and proteins from prokaryotes to vertebrates clustered under the newly established F-type lectin (FTL) family. We previously reported the purification and biochemical characterization of a fucose-binding protein (FBP) isolated from serum of the gilt head bream (Sparus aurata, SauFBP). In the present article, the complete coding sequence of SauFBP revealed that it is a member of the FTL family, consisting of two tandem carbohydrate recognition domains (CRD) that display the F-type sequence motif. In vitro opso…
F-Type Lectins: A highly diversified family of fucose-binding proteins with a unique sequence motif and structural fold, involved in self/non-self-recognition
The F-type lectin (FTL) family is one of the most recent to be identified and structurally characterized. Members of the FTL family are characterized by a fucose recognition domain [F-type lectin domain (FTLD)] that displays a novel jellyroll fold (“F-type” fold) and unique carbohydrate- and calcium-binding sequence motifs. This novel lectin family comprises widely distributed proteins exhibiting single, double, or greater multiples of the FTLD, either tandemly arrayed or combined with other structurally and functionally distinct domains, yielding lectin subunits of pleiotropic properties even within a single species. Furthermore, the extraordinary variability of FTL sequences (isoforms) th…