Full-length galectin-8 and separate carbohydrate recognition domains: the whole is greater than the sum of its parts?

2020 ◽  
Vol 48 (3) ◽  
pp. 1255-1268
Author(s):  
Alejandro J. Cagnoni ◽  
María F. Troncoso ◽  
Gabriel A. Rabinovich ◽  
Karina V. Mariño ◽  
María T. Elola
Keyword(s):  
Tandem Repeat ◽  
Cell Function ◽  
Full Length ◽  
Carbohydrate Recognition ◽  
Linker Peptide ◽  
Carbohydrate Recognition Domains ◽  
Function Relationship ◽  
Relationship Of ◽  
Group Structures

Galectin-8 (Gal-8) is a tandem-repeat type galectin with affinity for β-galactosides, bearing two carbohydrate recognition domains (CRD) connected by a linker peptide. The N- and C-terminal domains (Gal-8N and Gal-8C) share 35% homology, and their glycan ligand specificity is notably dissimilar: while Gal-8N shows strong affinity for α(2-3)-sialylated oligosaccharides, Gal-8C has higher affinity for non-sialylated oligosaccharides, including poly-N-acetyllactosamine and/ or A and B blood group structures. Particularly relevant for understanding the biological role of this lectin, full-length Gal-8 can bind cell surface glycoconjugates with broader affinity than the isolated Gal-8N and Gal-8C domains, a trait also described for other tandem-repeat galectins. Herein, we aim to discuss the potential use of separate CRDs in modelling tandem-repeat galectin-8 and its biological functions. For this purpose, we will cover several aspects of the structure–function relationship of this protein including crystallographic structures, glycan specificity, cell function and biological roles, with the ultimate goal of understanding the potential role of each CRD in predicting full-length Gal-8 involvement in relevant biological processes.

Galectin-8 tandem-repeat structure is essential for T-cell proliferation but not for co-stimulation

2011 ◽  
Vol 434 (1) ◽  
pp. 153-160 ◽  
Author(s):  
Valentina Cattaneo ◽  
María V. Tribulatti ◽  
Oscar Campetella
Keyword(s):  
T Cells ◽  
Tandem Repeat ◽  
Cd4 T Cells ◽  
Carbohydrate Recognition ◽  
Inhibition Of Proliferation ◽  
Proliferative Effect ◽  
Linker Peptide ◽  
Repeat Structure ◽  
Carbohydrate Recognition Domains ◽  
Group B

Gal (galectin)-8 is a tandem-repeat Gal containing N-CRDs (Nterminal carbohydrate-recognition domains) and C-CRDs (C-terminal carbohydrate-recognition domains) with differential glycan-binding specificity fused by a linker peptide. Gal-8 has two distinct effects on CD4 T-cells: at high concentrations it induces antigen-independent proliferation, whereas at low concentrations it co-stimulates antigen-specific responses. Associated Gal-8 structural requirements were dissected in the present study. Recombinant homodimers N–N (two N-terminal CRD chimaera) and C–C (two C-terminal CRD chimaera), but not single C-CRDs or N-CRDs, induced proliferation; however, single domains induced co-stimulation. These results indicate that the tandem-repeat structure was essential only for the proliferative effect, suggesting the involvement of lattice formation, whereas co-stimulation could be mediated by agonistic interactions. In both cases, C–C chimaeras displayed higher activity than Gal-8, indicating that the C-CRD was mainly involved, as was further supported by the strong inhibition of proliferation and co-stimulation in the presence of blood group B antigen, specifically recognized by this domain. Classic Gal inhibitors (lactose and thiodigalactoside) prevented proliferation but not co-stimulatory activity, which was inhibited by 3-O-β-D-galactopyranosyl-D-arabinose. Interestingly, Gal-8 induced proliferation of naïve human CD4 T-cells, varying from non- to high-responder individuals, whereas it promoted cell death of phytohaemagglutinin or CD3/CD28 pre-activated cells. The findings of the present study delineate the differential molecular requirements for Gal-8 activities on T-cells, and suggest a dual activity relying on activation state.

Role of aromatic residues in the structure-function relationship of .alpha.-bungarotoxin

Biochemistry ◽  
1982 ◽  
Vol 21 (11) ◽  
pp. 2592-2600 ◽  
Author(s):  
Yee Hsiung Chen ◽  
Jang Chyi Tai ◽  
Wan Jen Huang ◽  
Ming Zong Lai ◽  
Mien Chie Hung ◽  
...  
Keyword(s):  
Structure Function ◽  
Aromatic Residues ◽  
Structure Function Relationship ◽  
Function Relationship ◽  
Alpha Bungarotoxin ◽  
Relationship Of

Uncovering the ultrastructure of ramiform pits in the parenchyma cells of bamboo [Phyllostachys edulis (Carr.) J. Houz.]

Holzforschung ◽  
2020 ◽  
Vol 74 (3) ◽  
pp. 321-331 ◽  
Author(s):  
Caiping Lian ◽  
Shuqin Zhang ◽  
Xianmiao Liu ◽  
Junji Luo ◽  
Feng Yang ◽  
...  
Keyword(s):  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Type I ◽  
Aperture Diameter ◽  
Parenchyma Cells ◽  
Vascular Parenchyma ◽  
Function Relationship ◽  
Relationship Of ◽  
Important Evidence

AbstractPits are the main transverse channels of intercellular liquid transport in bamboo. Ramiform pits are a special type of simple pit with two or more branches. However, little is known about the morphology and physiological functions of ramiform pits. The anatomy of plants can provide important evidence for the role of cells. To better understand the ultrastructure and the structure-function relationship of ramiform pits, their characteristics need to be investigated. In this study, both qualitative and quantitative features of ramiform pits were studied using field-emission environmental scanning electron microscopy (FE-ESEM). The samples included the native structures and the replica structures obtained by resin castings. The results show that the ramiform pits have a diverse morphology that can be divided into main categories: type I (the primary branches) and type II (the secondary branches). The distribution of ramiform pits is different in ground parenchyma cells (GPCs) and vascular parenchyma cells (VPCs). The number, the pit aperture diameter and the pit canal length of ramiform pits in the VPCs were, respectively, greater (3-fold), larger (2–3-fold) and shorter (1.3-fold) than those in the GPCs.

scholarly journals The Role of the Fibronectin IGD Motif in Stimulating Fibroblast Migration

2007 ◽  
Vol 282 (49) ◽  
pp. 35530-35535 ◽  
Author(s):  
Christopher J. Millard ◽  
Ian R. Ellis ◽  
Andrew R. Pickford ◽  
Ana M. Schor ◽  
Seth L. Schor ◽  
...  
Keyword(s):  
Fibroblast Migration ◽  
Wide Range ◽  
Migration Stimulating Factor ◽  
Function Relationship ◽  
Relationship Of ◽  
Stimulating Factor ◽  
Insight Into ◽  
Stimulation Of

The motogenic activity of migration-stimulating factor, a truncated isoform of fibronectin (FN), has been attributed to the IGD motifs present in its FN type 1 modules. The structure-function relationship of various recombinant IGD-containing FN fragments is now investigated. Their structure is assessed by solution state NMR and their motogenic ability tested on fibroblasts. Even conservative mutations in the IGD motif are inactive or have severely reduced potency, while the structure remains essentially the same. A fragment with two IGD motifs is 100 times more active than a fragment with one and up to 106 times more than synthetic tetrapeptides. The wide range of potency in different contexts is discussed in terms of cryptic FN sites and cooperativity. These results give new insight into the stimulation of fibroblast migration by IGD motifs in FN.

scholarly journals CriTER-A: A Novel Temperature-Dependent Noncoding RNA Switch in the Telomeric Transcriptome of Chironomus riparius

2021 ◽  
Vol 22 (19) ◽  
pp. 10310
Author(s):  
Cristina Romero-López ◽  
Alfredo Berzal-Herranz ◽  
José Luis Martínez-Guitarte ◽  
Mercedes de la Fuente
Keyword(s):  
Thermal Stress ◽  
Noncoding Rna ◽  
Relative Proportion ◽  
Chironomus Riparius ◽  
Temperature Dependent ◽  
Differential Behaviour ◽  
High Sequence Homology ◽  
Function Relationship ◽  
Relationship Of

The telomeric transcriptome of Chironomus riparius has been involved in thermal stress response. One of the telomeric transcripts, the so-called CriTER-A variant, is highly overexpressed upon heat shock. On the other hand, its homologous variant CriTER-B, which is the most frequently encoded noncoding RNA in the telomeres of C. riparius, is only slightly affected by thermal stress. Interestingly, both transcripts show high sequence homology, but less is known about their folding and how this could influence their differential behaviour. Our study suggests that CriTER-A folds as two different conformers, whose relative proportion is influenced by temperature conditions. Meanwhile, the CriTER-B variant shows only one dominant conformer. Thus, a temperature-dependent conformational equilibrium can be established for CriTER-A, suggesting a putative functional role of the telomeric transcriptome in relation to thermal stress that could rely on the structure–function relationship of the CriTER-A transcripts.

scholarly journals Dynamics-function relationship of N-terminal acetyltransferases: the β6β7 loop modulates substrate accessibility to the catalytic site

2018 ◽  
Author(s):  
Angèle Abboud ◽  
Pierre Bédoucha ◽  
Jan Byška ◽  
Thomas Arnesen ◽  
Nathalie Reuter
Keyword(s):  
Normal Mode Analysis ◽  
Network Models ◽  
Catalytic Site ◽  
Mode Analysis ◽  
Ligand Specificity ◽  
Hairpin Loop ◽  
Domains Of Life ◽  
Function Relationship ◽  
Relationship Of

N-terminal acetyltransferases (NATs) are enzymes catalysing the transfer of the acetyl from Ac-CoA to the N-terminus of proteins, one of the most common protein modifications. Unlike NATs, lysine acetyltransferases (KATs) transfer an acetyl onto the amine group of internal lysines. To date, not much is known on the exclusive substrate specificity of NATs towards protein N-termini. All the NATs and some KATs share a common fold called GNAT. The main difference between NATs and KATs is an extra hairpin loop found only in NATs called β6β7 loop. It covers the active site as a lid. The hypothesized role of the loop is that of a barrier restricting the access to the catalytic site and preventing acetylation of internal lysines. We investigated the dynamics-function relationships of all available structures of NATs covering the three domains of life. Using elastic network models and normal mode analysis, we found a common dynamics pattern conserved through the GNAT fold; a rigid V-shaped groove, formed by the β4 and β5 strands and three relatively more dynamic loops α1α2, β3β4 and β6β7. We identified two independent dynamical domains in the GNAT fold, which is split at the β5 strand. We characterized the β6β7 hairpin loop slow dynamics and show that its movements are able to significantly widen the mouth of the ligand binding site thereby influencing its size and shape. Taken together our results show that NATs may have access to a broader ligand specificity range than anticipated.

scholarly journals Adherent cell function in murine T-lymphocyte antigen recognition. IV. Enhancement of murine T-cell antigen recognition by human leukocytic pyrogen.

1979 ◽  
Vol 150 (3) ◽  
pp. 709-714 ◽  
Author(s):  
L J Rosenwasser ◽  
C A Dinarello ◽  
A S Rosenthal
Keyword(s):  
T Cell ◽  
Cell Function ◽  
Keyhole Limpet Hemocyanin ◽  
Antigen Recognition ◽  
Mononuclear Phagocytes ◽  
Adherent Cell ◽  
Leukocytic Pyrogen ◽  
Relationship Of ◽  
The Relationship

A macrophage-dependent, antigen-specific murine T-cell proliferation assay was utilized to examine the role of soluble products of murine and human adherent cells in the activation of T lymphocytes. Highly purified human leukocytic pyrogen, and supernates from both murine and human mononuclear phagocytes-macrophages stimulated the immune T-cell proliferative response to the multideterminant antigens dinitrophenyl-ovalbumin and keyhole limpet hemocyanin. The implications of these studies and the relationship of leukocytic pyrogen to human lymphocyte-activating factor are discussed.

scholarly journals Structure-function relationship of a citrus salicylate methylesterase and role of salicylic acid in citrus canker resistance

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Caio Cesar de Lima Silva ◽  
Hugo Massayoshi Shimo ◽  
Rafael de Felício ◽  
Gustavo Fernando Mercaldi ◽  
Silvana Aparecida Rocco ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Structure Function ◽  
Citrus Canker ◽  
Structure Function Relationship ◽  
Function Relationship ◽  
Relationship Of
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