The Mechanism of β2m Molecule-Induced Changes in the Peptide Presentation Profile in a Bony Fish

Li, Zibin; Zhang, Nianzhi; Ma, Lizhen; Zhang, Lijie; Meng, Geng; Xia, Chun

doi:10.1016/j.isci.2020.101119

Cited by 15 publications

(10 citation statements)

References 51 publications

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“…Moreover, the inclusion of probiotics has been evaluated through the immune system gene expression such as interleukins, where Il-10 stands out, which is an immunosuppressive cytokine that prevents immune-mediated damage to the host by dampening inflammatory responses of the immune response (Howes et al 2014), the β2 microglobulin (b2m) is classified as part of the set of the immunoglobulin superfamily (IgSF) and play important roles in the adaptive immune system (Chen et al 2010). The immunological function of b2m is to assist classical major histocompatibility complex (MHC) class I (i.e., MHC-I) molecules in assembling endogenous antigen peptides, forming a trimolecular complex (i.e., pM-HC-I) and then presenting them to the surface of antigen-presenting cells (APCs); through interaction with T cell receptors (TCRs), specific cytotoxic T lymphocyte (CTL) immunity is thus induced (Flajnik and Kasahara 2001;Li et al 2020), and the transforming growth factor β1 (tgf-β1), which is an important multifunctional cytokine involved in the regulation of cell proliferation, differentiation, survival, migration, and apoptosis under physiological and pathological conditions (Qi et al 2016). For example, tgf-β1 acts as an immunosuppressive mediator and inhibits nitric oxide production in TNF-γ-activated macrophages in fish (Wang et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Dietary live yeast (Debaryomyces hansenii) provides no advantages in tropical gar, Atractosteus tropicus (Actinopterygii: Lepisosteiformes: Lepisosteidae), juvenile aquaculture

Hernández-López¹,

Tovar‐Ramírez²,

Rosa-García³

et al. 2021

AIeP

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Tropical gar, Atractosteus tropicus Gill, 1863, is an ancient freshwater fish that is commercially cultivated in southern Mexico. Currently, there is a specific diet for its culture; however, the addition of probiotics has not been investigated. The objective of this study was to evaluate the supplementation of live yeast Debaryomyces hansenii for A. tropicus juveniles on growth, productive parameters, survival, somatic index, digestive enzyme activity, and immune system gene expressions (interleukin 10, il-10, Transforming growth factor β1, tgf-β1, and β2 microglobulin, b2m). Three experimental diets increased the dose of live yeast (0.5, 1.0, and 1.5%; 1014, 1015, and 1016CFU g diet–1, respectively) and a control diet (CD; without yeast) were designed. Daily weight gain and specific growth rate were higher in fish fed with CD and 0.5% D. hansenii. High activities of trypsin, chymotrypsin LAP, and α-amylase, as well as overexpression of il-10 in the spleen, were detected in fish feed 0.5% D. hansenii. The inclusion of D. hansenii had no positive effect on aquaculture for A. tropicus, lower doses should be tested to optimize the diet.

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Section: Introductionmentioning

confidence: 99%

Dietary live yeast (Debaryomyces hansenii) provides no advantages in tropical gar, Atractosteus tropicus (Actinopterygii: Lepisosteiformes: Lepisosteidae), juvenile aquaculture

Hernández-López¹,

Tovar‐Ramírez²,

Rosa-García³

et al. 2021

AIeP

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“…Nevertheless, there are indications for the involvement of b 2 -m in "tuning" the peptide binding groove-rather than being a simple "lock" for the pMHC-I complex-as, for example, shown by a recent study of our group in carp. Namely, in two carp pMHC-I structures with identical HC and peptide, but with different, naturally occurring, paralogous b 2m variants, the peptide was bound in a different conformation (58). This finding in carp was not unexpected, since earlier reports had found that naturally occurring allelic variation in mouse b 2 -m is associated with differences in peptides presented by MHC-I (91) and T cell stimulation (91,92).…”

Section: Discussionmentioning

confidence: 82%

“…With the elucidation of shark pUAA, pMHC-I structures are now known for a variety of placental mammals (36,51,53), including chickens and ducks (5456), the amphibian African clawed frog (57), the bony fish grass carp (41,58), and the nurse shark (Fig. 2Ba).…”

Section: Resultsmentioning

confidence: 99%

The Structure of a Peptide-Loaded Shark MHC Class I Molecule Reveals Features of the Binding between β2-Microglobulin and H Chain Conserved in Evolution

Zhang

Wei

et al. 2021

The Journal of Immunology

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Cartilaginous fish are the most primitive extant species with MHC molecules. Using the nurse shark, the current study is, to the best of our knowledge, the first to present a peptide-loaded MHC class I (pMHC-I) structure for this class of animals. The overall structure was found to be similar between cartilaginous fish and bony animals, showing remarkable conservation of interactions between the three pMHC-I components H chain, β2-microglobulin (β2-m), and peptide ligand. In most previous studies, relatively little attention was given to the details of binding between the H chain and β2-m, and our study provides important new insights. A pronounced conserved feature involves the insertion of a large β2-m F56+W60 hydrophobic knob into a pleat of the β-sheet floor of the H chain α1α2 domain, with the knob being surrounded by conserved residues. Another conserved feature is a hydrogen bond between β2-m Y10 and a proline in the α3 domain of the H chain. By alanine substitution analysis, we found that the conserved β2-m residues Y10, D53, F56, and W60—each binding the H chain—are required for stable pMHC-I complex formation. For the β2-m residues Y10 and F56, such observations have not been reported before. The combined data indicate that for stable pMHC-I complex formation β2-m should not only bind the α1α2 domain but also the α3 domain. Knowing the conserved structural features of pMHC-I should be helpful for future elucidations of the mechanisms of pMHC-I complex formation and peptide editing.

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“…Structures of pMHC-I have now been determined throughout the major clades of jawed vertebrates including cartilaginous fish (27), bony fish (28,29), amphibians (30), the birds chicken [e.g., (31)(32)(33)] and duck (34), and a variety of mammals [e.g., (4,(35)(36)(37)(38)], whereas pMHC-II structures only have been determined for chicken (39), mouse [e.g., (40)], and human [e.g., (5)]; most of the here listed studies in primitive vertebrates were performed by our group. This recent accumulation of MHC structural information across widely divergent species invites a deeper analysis of MHC evolution.…”

Section: Introductionmentioning

confidence: 99%

Structural Comparison Between MHC Classes I and II; in Evolution, a Class-II-Like Molecule Probably Came First

Zhang

Hashimoto

et al. 2021

Front. Immunol.

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Structures of peptide-loaded major histocompatibility complex class I (pMHC-I) and class II (pMHC-II) complexes are similar. However, whereas pMHC-II complexes include similar-sized IIα and IIβ chains, pMHC-I complexes include a heavy chain (HC) and a single domain molecule β2-microglobulin (β2-m). Recently, we elucidated several pMHC-I and pMHC-II structures of primitive vertebrate species. In the present study, a comprehensive comparison of pMHC-I and pMHC-II structures helps to understand pMHC structural evolution and supports the earlier proposed—though debated—direction of MHC evolution from class II-type to class I. Extant pMHC-II structures share major functional characteristics with a deduced MHC-II-type homodimer ancestor. Evolutionary establishment of pMHC-I presumably involved important new functions such as (i) increased peptide selectivity by binding the peptides in a closed groove (ii), structural amplification of peptide ligand sequence differences by binding in a non-relaxed fashion, and (iii) increased peptide selectivity by syngeneic heterotrimer complex formation between peptide, HC, and β2-m. These new functions were associated with structures that since their establishment in early pMHC-I have been very well conserved, including a shifted and reorganized P1 pocket (aka A pocket), and insertion of a β2-m hydrophobic knob into the peptide binding domain β-sheet floor. A comparison between divergent species indicates better sequence conservation of peptide binding domains among MHC-I than among MHC-II, agreeing with more demanding interactions within pMHC-I complexes. In lungfishes, genes encoding fusions of all MHC-IIα and MHC-IIβ extracellular domains were identified, and although these lungfish genes presumably derived from classical MHC-II, they provide an alternative mechanistic hypothesis for how evolution from class II-type to class I may have occurred.

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The Mechanism of β2m Molecule-Induced Changes in the Peptide Presentation Profile in a Bony Fish

Cited by 15 publications

References 51 publications

Dietary live yeast (Debaryomyces hansenii) provides no advantages in tropical gar, Atractosteus tropicus (Actinopterygii: Lepisosteiformes: Lepisosteidae), juvenile aquaculture

Dietary live yeast (Debaryomyces hansenii) provides no advantages in tropical gar, Atractosteus tropicus (Actinopterygii: Lepisosteiformes: Lepisosteidae), juvenile aquaculture

The Structure of a Peptide-Loaded Shark MHC Class I Molecule Reveals Features of the Binding between β2-Microglobulin and H Chain Conserved in Evolution

Structural Comparison Between MHC Classes I and II; in Evolution, a Class-II-Like Molecule Probably Came First

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