Carbohydrate‐binding agents act as potent trypanocidals that elicit modifications in <scp>VSG</scp> glycosylation and reduced virulence in <i><scp>T</scp>rypanosoma brucei</i>

Castillo-Acosta, Víctor M.; Vidal, Antonio E.; Ruíz-Pérez, Luis M.; Damme, Els J.M. Van; Igarashi, Yasuhiro; Balzarini, Jan; González-Pacanowska, Dolores

doi:10.1111/mmi.12359

Cited by 12 publications

(42 citation statements)

References 47 publications

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“…Involvement of region 1 in sequon specificity of TbSTT3B and TbSTT3C has been previously demonstrated, whereupon genetic rearrangements a chimeric gene was generated containing the first variable region of TbSTT3C flanked by TbSTT3B sequences. The chimeric TbSTT3B/C/B protein described in this study showed much less efficient recognition of the native substrate of TbSTT3B, whereas it appeared to have attained a peptide acceptor specificity more similar to TbSTT3A than TbSTT3B (21).…”

Section: Distinct Protein Region Influences Polypeptide Specificity Omentioning

confidence: 66%

“…N-Glycosylation epitopes on VSG play an important role in T. brucei virulence (20). Furthermore, a possible immune evasion strategy has been proposed where T. brucei genetically recombined its N-glycosylation machinery, resulting in the change of the glycosylation status of VSG (21). The T. brucei genome encodes three paralogues of STT3 termed TbSTT3A, TbSTT3B, and TbSTT3C (19,22).…”

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confidence: 99%

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Analysis of substrate specificity of Trypanosoma brucei oligosaccharyltransferases (OSTs) by functional expression of domain-swapped chimeras in yeast

Poljak¹,

Breitling

Gauss³

et al. 2017

Journal of Biological Chemistry

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-Linked protein glycosylation is an essential and highly conserved post-translational modification in eukaryotes. The transfer of a glycan from a lipid-linked oligosaccharide (LLO) donor to the asparagine residue of a nascent polypeptide chain is catalyzed by an oligosaccharyltransferase (OST) in the lumen of the endoplasmic reticulum (ER). encodes three paralogue single-protein OSTs calledSTT3A, STT3B, andSTT3C that can functionally complement the OST, making it an ideal experimental system to study the fundamental properties of OST activity. We characterized the LLO and polypeptide specificity of all threeOST isoforms and their chimeric forms in the heterologous expression host where we were able to apply yeast genetic tools and newly developed glycoproteomics methods. We demonstrated thatSTT3A accepted LLO substrates ranging from ManGlcNAc to ManGlcNAc In contrast, STT3B required more complex precursors ranging from ManGlcNAc to GlcManGlcNAc structures, and STT3C did not display any LLO preference. Sequence differences between the isoforms cluster in three distinct regions. We have swapped the individual regions between different OST proteins and identified region 2 to influence the specificity toward the LLO and region 1 to influence polypeptide substrate specificity. These results provide a basis to further investigate the molecular mechanisms and contribution of single amino acids in OST interaction with its substrates.

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Section: Distinct Protein Region Influences Polypeptide Specificity Omentioning

confidence: 66%

mentioning

confidence: 99%

Analysis of substrate specificity of Trypanosoma brucei oligosaccharyltransferases (OSTs) by functional expression of domain-swapped chimeras in yeast

Poljak¹,

Breitling

Gauss³

et al. 2017

Journal of Biological Chemistry

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“…Fluid-phase endocytosis was determined using Alexa Fluor® 488-labelled dextran 10,000 (Molecular Probes) as reported elsewhere [75]. 3 x 10 6 parasites were resuspended in 10 μl of TDB-glucose plus 1% BSA and incubated at 37°C for 10 min.…”

Section: Methodsmentioning

confidence: 99%

Trypanosoma brucei gambiense Adaptation to Different Mammalian Sera Is Associated with VSG Expression Site Plasticity

et al. 2013

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Trypanosoma brucei gambiense infection is widely considered an anthroponosis, although it has also been found in wild and domestic animals. Thus, fauna could act as reservoir, constraining the elimination of the parasite in hypo-endemic foci. To better understand the possible maintenance of T. b. gambiense in local fauna and investigate the molecular mechanisms underlying adaptation, we generated adapted cells lines (ACLs) by in vitro culture of the parasites in different mammalian sera. Using specific antibodies against the Variant Surface Glycoproteins (VSGs) we found that serum ACLs exhibited different VSG variants when maintained in pig, goat or human sera. Although newly detected VSGs were independent of the sera used, the consistent appearance of different VSGs suggested remodelling of the co-transcribed genes at the telomeric Expression Site (VSG-ES). Thus, Expression Site Associated Genes (ESAGs) sequences were analysed to investigate possible polymorphism selection. ESAGs 6 and 7 genotypes, encoding the transferrin receptor (TfR), expressed in different ACLs were characterised. In addition, we quantified the ESAG6/7 mRNA levels and analysed transferrin (Tf) uptake. Interestingly, the best growth occurred in pig and human serum ACLs, which consistently exhibited a predominant ESAG7 genotype and higher Tf uptake than those obtained in calf and goat sera. We also detected an apparent selection of specific ESAG3 genotypes in the pig and human serum ACLs, suggesting that other ESAGs could be involved in the host adaptation processes. Altogether, these results suggest a model whereby VSG-ES remodelling allows the parasite to express a specific set of ESAGs to provide selective advantages in different hosts. Finally, pig serum ACLs display phenotypic adaptation parameters closely related to human serum ACLs but distinct to parasites grown in calf and goat sera. These results suggest a better suitability of swine to maintain T. b. gambiense infection supporting previous epidemiological results.

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“…Collectively, these studies demonstrate that trypanosomes decorate their proteins with homogeneous PMGs at varying levels during their complex life stages, suggesting stage‐specific functions of parasitic PMPs. For example, the T. brucei PMPs may have roles in facilitating host–parasite interactions and in the growth of the parasite, as indicated by parasite growth abrogation and impaired endocytosis upon in vitro incubation of the parasite with PMP‐recognising Man‐ and GlcNAc‐specific Hippeastrum hybrid agglutinin and stinging nettle lectin (Castillo‐Acosta et al ., , ). There are still no reports of human lectin receptors recognising trypanosomatid M3‐modified glycoproteins to shed light on whether similar lectin‐PMP interactions are involved in T. brucei ‐based infections in humans.…”

Section: Surveying Pmps Across the Eukaryotic Kingdoms And Phylamentioning

confidence: 99%

Human protein paucimannosylation: cues from the eukaryotic kingdoms

et al. 2019

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Paucimannosidic proteins (PMPs) are bioactive glycoproteins carrying truncated α-or β-mannosyl-terminating asparagine (N )-linked glycans widely reported across the eukaryotic domain. Our understanding of human PMPs remains limited, despite findings documenting their existence and association with human disease glycobiology. This review comprehensively surveys the structures, biosynthetic routes and functions of PMPs across the eukaryotic kingdoms with the aim of synthesising an improved understanding on the role of protein paucimannosylation in human health and diseases. Convincing biochemical, glycoanalytical and biological data detail a vast structural heterogeneity and fascinating tissue-and subcellular-specific expression of PMPs within invertebrates and plants, often comprising multi-α1,3/6-fucosylation and β1,2-xylosylation amongst other glycan modifications and non-glycan substitutions e.g. O-methylation. Vertebrates and protists express less-heterogeneous PMPs typically only comprising variable core fucosylation of bi-and trimannosylchitobiose core glycans. In particular, the Manα1,6Manβ1,4GlcNAc(α1,6Fuc)β1,4GlcNAcβAsn glycan (M2F) decorates various human neutrophil proteins reportedly displaying bioactivity and structural integrity demonstrating that they are not degradation products. Less-truncated paucimannosidic glycans (e.g. M3F) are characteristic glycosylation features of proteins expressed by human cancer and stem cells. Concertedly, these observations suggest the involvement of human PMPs in processes related to innate immunity, tumorigenesis and cellular differentiation. The absence of human PMPs in diverse bodily fluids studied under many (patho)physiological conditions suggests extravascular residence and points to localised functions of PMPs in peripheral tissues. Absence of PMPs in Fungi indicates that paucimannosylation is common, but not universally conserved, in eukaryotes. Relative to human PMPs, the expression of PMPs in plants, invertebrates and protists is more tissue-wide and constitutive yet, similar to their human counterparts, PMP expression remains regulated by the physiology of the producing organism and PMPs evidently serve essential functions in development, cell-cell communication and host-pathogen/symbiont interactions. In most PMP-producing organisms, including humans, the N -acetyl-β-hexosaminidase isoenzymes and linkage-specific α-mannosidases are glycoside hydrolases critical for generating PMPs via N -acetylglucosaminyltransferase I (GnT-I)-dependent and GnT-I-independent truncation pathways. However, the identity and structure of many species-specific PMPs in eukaryotes, their biosynthetic routes, strong tissue-and development-specific expression, and diverse functions are still elusive. Deep exploration of these PMP features involving, for example, the characterisation of endogenous PMP-recognising lectins across a variety of healthy and N -acetyl-β-hexosaminidase-deficient human tissue types and identification of microbial adhesins reactive to human PMPs, are amongs...

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Carbohydrate‐binding agents act as potent trypanocidals that elicit modifications in VSG glycosylation and reduced virulence in Trypanosoma brucei

Cited by 12 publications

References 47 publications

Analysis of substrate specificity of Trypanosoma brucei oligosaccharyltransferases (OSTs) by functional expression of domain-swapped chimeras in yeast

Analysis of substrate specificity of Trypanosoma brucei oligosaccharyltransferases (OSTs) by functional expression of domain-swapped chimeras in yeast

Trypanosoma brucei gambiense Adaptation to Different Mammalian Sera Is Associated with VSG Expression Site Plasticity

Human protein paucimannosylation: cues from the eukaryotic kingdoms

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