Functional Analysis of the Glucuronyltransferases GlcAT-P and GlcAT-S of Drosophila melanogaster: Distinct Activities towards the O-linked T-antigen

Breloy, Isabelle; Schwientek, Tilo; Althoff, Deborah; Holz, Marvin C.; Koppen, Tim; Krupa, Angelika; Hanisch, Franz‐Georg

doi:10.3390/biom6010008

Cited by 8 publications

(4 citation statements)

References 25 publications

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“…18% of T antigen in the embryo has been found to be further modified, predominantly by glucuronic acid (GlcA) ( Aoki et al, 2008 ). Of the three GlcA transferases found in Drosophila only GlcAT-P is robustly capable of adding GlcA onto the T O-glycan structure in cells ( Breloy et al, 2016 ; Itoh et al, 2018 ; Kim et al, 2003 ). To examine if the specific defect in germband invasion that we observed by blocking the formation of T antigen is due to the need for a further elaboration by GlcA, we utilized a lethal MI{MIC} transposon insertion mutant in the GlcAT-P gene.…”

Section: Resultsmentioning

confidence: 99%

A conserved major facilitator superfamily member orchestrates a subset of O-glycosylation to aid macrophage tissue invasion

Valosková

Biebl

Roblek

et al. 2019

eLife

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Aberrant display of the truncated core1 O-glycan T-antigen is a common feature of human cancer cells that correlates with metastasis. Here we show that T-antigen in Drosophila melanogaster macrophages is involved in their developmentally programmed tissue invasion. Higher macrophage T-antigen levels require an atypical major facilitator superfamily (MFS) member that we named Minerva which enables macrophage dissemination and invasion. We characterize for the first time the T and Tn glycoform O-glycoproteome of the Drosophila melanogaster embryo, and determine that Minerva increases the presence of T-antigen on proteins in pathways previously linked to cancer, most strongly on the sulfhydryl oxidase Qsox1 which we show is required for macrophage tissue entry. Minerva’s vertebrate ortholog, MFSD1, rescues the minerva mutant’s migration and T-antigen glycosylation defects. We thus identify a key conserved regulator that orchestrates O-glycosylation on a protein subset to activate a program governing migration steps important for both development and cancer metastasis.

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Section: Resultsmentioning

confidence: 99%

A conserved major facilitator superfamily member orchestrates a subset of O-glycosylation to aid macrophage tissue invasion

Valosková

Biebl

Roblek

et al. 2019

eLife

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“…Previous studies showed that both dGlcAT-P and dGlcAT-S can catalyze glucuronylation of N -linked HNK-1 epitope (GlcAβ1-3Galβ1-4GlcNAc; Kim et al, 2003; Breloy et al, 2016). However, the expression level of HNK-1 epitope was hardly reduced in dGlcAT-P null mutant larvae (Pandey et al, 2011), indicating that dGlcAT-P was not the key enzyme for HNK-1 epitope glucuronylation in Drosophila larvae.…”

Section: Discussionmentioning

confidence: 99%

“…Three Drosophila β1,3-glucuronyltransferases (dGlcATs), dGlcAT-I (DmGlcAT-I), dGlcAT-S (DmGlcAT-BSI), and dGlcAT-P (DmGlcAT-BSII), have been reported in Drosophila . Previous studies showed that both dGlcAT-P and dGlcAT-S could transfer GlcA to T antigen in vitro , whereas only dGlcAT-P modified T antigen in S2 cells (Kim et al, 2003; Breloy et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Glucuronylated core 1 glycans are required for precise localization of neuromuscular junctions and normal formation of basement membranes on Drosophila muscles

Itoh

Akimoto

Kondo

et al. 2018

Developmental Biology

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T antigen (Galβ1-3GalNAcα1-Ser/Thr) is an evolutionary-conserved mucin-type core 1 glycan structure in animals synthesized by core 1 β1,3-galactosyltransferase 1 (C1GalT1). Previous studies showed that T antigen produced by Drosophila C1GalT1 (dC1GalT1) was expressed in various tissues and dC1GalT1 loss in larvae led to various defects, including decreased number of circulating hemocytes, hyper-differentiation of hematopoietic stem cells in lymph glands, malformation of the central nervous system, mislocalization of neuromuscular junction (NMJ) boutons, and ultrastructural abnormalities in NMJs and muscle cells. Although glucuronylated T antigen (GlcAβ1-3Galβ1-3GalNAcα1-Ser/Thr) has been identified in Drosophila, the physiological function of this structure has not yet been clarified. In this study, for the first time, we unraveled biological roles of glucuronylated T antigen. Our data show that in Drosophila, glucuronylation of T antigen is predominantly carried out by Drosophila β1,3-glucuronyltransferase-P (dGlcAT-P). We created dGlcAT-P null mutants and found that mutant larvae showed lower expression of glucuronylated T antigen on the muscles and at NMJs. Furthermore, mislocalization of NMJ boutons and a partial loss of the basement membrane components collagen IV (Col IV) and nidogen (Ndg) at the muscle 6/7 boundary were observed. Those two phenotypes were correlated and identical to previously described phenotypes in dC1GalT1 mutant larvae. In addition, dGlcAT-P null mutants exhibited fewer NMJ branches on muscles 6/7. Moreover, ultrastructural analysis revealed that basement membranes that lacked Col IV and Ndg were significantly deformed. We also found that the loss of dGlcAT-P expression caused ultrastructural defects in NMJ boutons. Finally, we showed a genetic interaction between dGlcAT-P and dC1GalT1. Therefore, these results demonstrate that glucuronylated core 1 glycans synthesized by dGlcAT-P are key modulators of NMJ bouton localization, basement membrane formation, and NMJ arborization on larval muscles.

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“…In addition, although one sialyltranseferase (SiaT) has been identified in Drosophila , it does not show catalytic activity for the transfer of sialic acid (Sia) to T antigen (Koles et al, 2004 ). Instead of the synthesis of sialylated T antigen in Drosophila , glucuronylated T antigen is produced by β1, 3-glucuronyltransferase-P (dGlcAT-P), which predominantly transfers glucuronic acid (GlcA) to the Gal residue in a β1, 3-linkage (Kim et al, 2003 ; Breloy et al, 2016 ; Itoh et al, 2018 ). Therefore, Drosophila glucuronylated T antigen is considered to correspond to mammalian sialylated T antigen because the two glycan structures contain negatively charged monosaccharides, namely, GlcA and Sia.…”

Section: Introductionmentioning

confidence: 99%

Mucin-Type O-Glycosylation in the Drosophila Nervous System

Itoh

Nishihara

2021

Front. Neuroanat.

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Mucin-type O-glycosylation, a predominant type of O-glycosylation, is an evolutionarily conserved posttranslational modification in animals. Mucin-type O-glycans are often found on mucins in the mucous membranes of the digestive tract. These glycan structures are also expressed in other cell types, such as blood cells and nephrocytes, and have crucial physiological functions. Altered expression of mucin-type O-glycans is known to be associated with several human disorders, including Tn syndrome and cancer; however, the physiological roles of mucin-type O-glycans in the mammalian brain remains largely unknown. The functions of mucin-type O-glycans have been studied in the fruit fly, Drosophila melanogaster. The basic structures of mucin-type O-glycans, including Tn antigen (GalNAcα1-Ser/Thr) and T antigen (Galβ1–3GalNAcα1-Ser/Thr), as well as the glycosyltransferases that synthesize them, are conserved between Drosophila and mammals. These mucin-type O-glycans are expressed in the Drosophila nervous system, including the central nervous system (CNS) and neuromuscular junctions (NMJs). In primary cultured neurons of Drosophila, mucin-type O-glycans show a characteristic localization pattern in axons. Phenotypic analyses using mutants of glycosyltransferase genes have revealed that mucin-type O-glycans are required for CNS development, NMJ morphogenesis, and synaptic functions of NMJs in Drosophila. In this review, we describe the roles of mucin-type O-glycans in the Drosophila nervous system. These findings will provide insight into the functions of mucin-type O-glycans in the mammalian brain.

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Functional Analysis of the Glucuronyltransferases GlcAT-P and GlcAT-S of Drosophila melanogaster: Distinct Activities towards the O-linked T-antigen

Cited by 8 publications

References 25 publications

A conserved major facilitator superfamily member orchestrates a subset of O-glycosylation to aid macrophage tissue invasion

A conserved major facilitator superfamily member orchestrates a subset of O-glycosylation to aid macrophage tissue invasion

Glucuronylated core 1 glycans are required for precise localization of neuromuscular junctions and normal formation of basement membranes on Drosophila muscles

Mucin-Type O-Glycosylation in the Drosophila Nervous System

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