Browse
Submit Data
Databases
API
Help

Dataset Information

20 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

N-glycan trimming by glucosidase II is essential for Arabidopsis development.

ABSTRACT: Glucosidase II, one of the early N-glycan processing enzymes and a major player in the glycoprotein folding quality control, has been described as a soluble heterodimer composed of alpha and beta subunits. Here we present the first characterization of a plant glucosidase II alpha subunit at the molecular level. Expression of the Arabidopsis alpha subunit restored N-glycan maturation capacity in Schizosaccharomyces pombe alpha- or alphabeta-deficient mutants, but with a lower efficiency in the last case. Inactivation of the alpha subunit in a temperature sensitive Arabidopsis mutant blocked N-glycan processing after a first trimming by glucosidase I and strongly affected seedling development.

SUBMITTER: Soussilane P

PROVIDER: S-EPMC2741616 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

N-glycan trimming by glucosidase II is essential for Arabidopsis development.

Soussilane Pravina P D'Alessio Cecilia C Paccalet Thomas T Fitchette Anne-Catherine AC Parodi Armando J AJ Williamson Richard R Plasson Carole C Faye Loïc L Gomord Véronique V

Glycoconjugate journal 20081030 5

Glucosidase II, one of the early N-glycan processing enzymes and a major player in the glycoprotein folding quality control, has been described as a soluble heterodimer composed of alpha and beta subunits. Here we present the first characterization of a plant glucosidase II alpha subunit at the molecular level. Expression of the Arabidopsis alpha subunit restored N-glycan maturation capacity in Schizosaccharomyces pombe alpha- or alphabeta-deficient mutants, but with a lower efficiency in the la ...[more]

PMID: 18972207

Similar Datasets

Arabidopsis glucosidase I mutants reveal a critical role of N-glycan trimming in seed development.

Project description:Glycoproteins with asparagine-linked (N-linked) glycans occur in all eukaryotic cells. The function of their glycan moieties is one of the central problems in contemporary cell biology. N-glycosylation may modify physicochemical and biological protein properties such as conformation, degradation, intracellular sorting or secretion. We have isolated and characterized two allelic Arabidopsis mutants, gcs1-1 and gcs1-2, which produce abnormal shrunken seeds, blocked at the heart stage of development. The mutant seeds accumulate a low level of storage proteins, have no typical protein bodies, display abnormal cell enlargement and show occasional cell wall disruptions. The mutated gene has been cloned by T-DNA tagging. It codes for a protein homologous to animal and yeast alpha-glucosidase I, an enzyme that controls the first committed step for N-glycan trimming. Biochemical analyses have confirmed that trimming of the alpha1,2- linked glucosyl residue constitutive of the N-glycan precursor is blocked in this mutant. These results demonstrate the importance of N-glycan trimming for the accumulation of seed storage proteins, the formation of protein bodies, cell differentiation and embryo development.

| S-EPMC145462 | biostudies-literature

Glucosidase II beta subunit modulates N-glycan trimming in fission yeasts and mammals.

Project description:Glucosidase II (GII) plays a key role in glycoprotein biogenesis in the endoplasmic reticulum (ER). It is responsible for the sequential removal of the two innermost glucose residues from the glycan (Glc(3)Man(9)GlcNAc(2)) transferred to Asn residues in proteins. GII participates in the calnexin/calreticulin cycle; it removes the single glucose unit added to folding intermediates and misfolded glycoproteins by the UDP-Glc:glycoprotein glucosyltransferase. GII is a heterodimer whose alpha subunit (GIIalpha) bears the glycosyl hydrolase active site, whereas its beta subunit (GIIbeta) role is controversial and has been reported to be involved in GIIalpha ER retention and folding. Here, we report that in the absence of GIIbeta, the catalytic subunit GIIalpha of the fission yeast Schizosaccharomyces pombe (an organism displaying a glycoprotein folding quality control mechanism similar to that occurring in mammalian cells) folds to an active conformation able to hydrolyze p-nitrophenyl alpha-d-glucopyranoside. However, the heterodimer is required to efficiently deglucosylate the physiological substrates Glc(2)Man(9)GlcNAc(2) (G2M9) and Glc(1)Man(9)GlcNAc(2) (G1M9). The interaction of the mannose 6-phosphate receptor homologous domain present in GIIbeta and mannoses in the B and/or C arms of the glycans mediates glycan hydrolysis enhancement. We present evidence that also in mammalian cells GIIbeta modulates G2M9 and G1M9 trimming.

| S-EPMC2735495 | biostudies-literature

Structural basis for two-step glucose trimming by glucosidase II involved in ER glycoprotein quality control.

Project description:The endoplasmic reticulum (ER) has a sophisticated protein quality control system for the efficient folding of newly synthesized proteins. In this system, a variety of N-linked oligosaccharides displayed on proteins serve as signals recognized by series of intracellular lectins. Glucosidase II catalyzes two-step hydrolysis at α1,3-linked glucose-glucose and glucose-mannose residues of high-mannose-type glycans to generate a quality control protein tag that is transiently expressed on glycoproteins and recognized by ER chaperones. Here we determined the crystal structures of the catalytic α subunit of glucosidase II (GIIα) complexed with two different glucosyl ligands containing the scissile bonds of first- and second-step reactions. Our structural data revealed that the nonreducing terminal disaccharide moieties of the two kinds of substrates can be accommodated in a gourd-shaped bilocular pocket, thereby providing a structural basis for substrate-binding specificity in the two-step deglucosylation catalyzed by this enzyme.

| S-EPMC4742823 | biostudies-literature

Protein N-glycosylation and N-glycan trimming are required for postembryonic development of the pest beetle Tribolium castaneum.

Project description:In holometabolous insects the transition from larva to adult requires a complete body reorganization and relies on N-glycosylated proteins. N-glycosylation is an important posttranslational modification that influences protein activity but its impact on the metamorphosis has not been studied yet. Here we used the red flour beetle, Tribolium castaneum, to perform a first comprehensive study on the involvement of the protein N-glycosylation pathway in metamorphosis. The transcript levels for genes encoding N-glycan processing enzymes increased during later developmental stages and, in turn, transition from larva to adult coincided with an enrichment of more extensively modified paucimannose glycans, including fucosylated ones. Blockage of N-glycan attachment resulted in larval mortality, while RNAi of α-glucosidases involved in early N-glycan trimming and quality control disrupted the larva to pupa transition. Additionally, simultaneous knockdown of multiple genes responsible for N-glycan processing towards paucimannose structures revealed their novel roles in pupal appendage formation and adult eclosion. Our findings revealed that, next to hormonal control, insect post-embryonic development and metamorphosis depend on protein N-glycan attachment and efficient N-glycan processing. Consequently, disruption of these processes could be an effective new approach for insect control.

| S-EPMC5059678 | biostudies-literature

Glucosidase II and N-glycan mannose content regulate the half-lives of monoglucosylated species in vivo.

Project description:Glucosidase II (GII) sequentially removes the two innermost glucose residues from the glycan (Glc(3)Man(9)GlcNAc(2)) transferred to proteins. GII also participates in cycles involving the lectin/chaperones calnexin (CNX) and calreticulin (CRT) as it removes the single glucose unit added to folding intermediates and misfolded glycoproteins by the UDP-Glc:glycoprotein glucosyltransferase (UGGT). GII is a heterodimer in which the ? subunit (GII?) bears the active site, and the ? subunit (GII?) modulates GII? activity through its C-terminal mannose 6-phosphate receptor homologous (MRH) domain. Here we report that, as already described in cell-free assays, in live Schizosaccharomyces pombe cells a decrease in the number of mannoses in the glycan results in decreased GII activity. Contrary to previously reported cell-free experiments, however, no such effect was observed in vivo for UGGT. We propose that endoplasmic reticulum ?-mannosidase-mediated N-glycan demannosylation of misfolded/slow-folding glycoproteins may favor their interaction with the lectin/chaperone CNX present in S. pombe by prolonging the half-lives of the monoglucosylated glycans (S. pombe lacks CRT). Moreover, we show that even N-glycans bearing five mannoses may interact in vivo with the GII? MRH domain and that the N-terminal GII? G2B domain is involved in the GII?-GII? interaction. Finally, we report that protists that transfer glycans with low mannose content to proteins have nevertheless conserved the possibility of displaying relatively long-lived monoglucosylated glycans by expressing GII? MRH domains with a higher specificity for glycans with high mannose content.

| S-EPMC3103398 | biostudies-literature

Lipid disequilibrium disrupts ER proteostasis by impairing ERAD substrate glycan trimming and dislocation.

Project description:The endoplasmic reticulum (ER) mediates the folding, maturation, and deployment of the secretory proteome. Proteins that fail to achieve their native conformation are retained in the ER and targeted for clearance by ER-associated degradation (ERAD), a sophisticated process that mediates the ubiquitin-dependent delivery of substrates to the 26S proteasome for proteolysis. Recent findings indicate that inhibition of long-chain acyl-CoA synthetases with triacsin C, a fatty acid analogue, impairs lipid droplet (LD) biogenesis and ERAD, suggesting a role for LDs in ERAD. However, whether LDs are involved in the ERAD process remains an outstanding question. Using chemical and genetic approaches to disrupt diacylglycerol acyltransferase (DGAT)-dependent LD biogenesis, we provide evidence that LDs are dispensable for ERAD in mammalian cells. Instead, our results suggest that triacsin C causes global alterations in the cellular lipid landscape that disrupt ER proteostasis by interfering with the glycan trimming and dislocation steps of ERAD. Prolonged triacsin C treatment activates both the IRE1 and PERK branches of the unfolded protein response and ultimately leads to IRE1-dependent cell death. These findings identify an intimate relationship between fatty acid metabolism and ER proteostasis that influences cell viability.

| S-EPMC5231896 | biostudies-literature

Hydroxyproline-<i>O</i>-Galactosyltransferases Synthesizing Type II Arabinogalactans Are Essential for Male Gametophytic Development in Arabidopsis.

Project description:In flowering plants, male reproductive function is determined by successful development and performance of stamens, pollen grains, and pollen tubes. Despite the crucial role of highly glycosylated arabinogalactan-proteins (AGPs) in male gamete formation, pollen grain, and pollen tube cell walls, the underlying mechanisms defining these functions of AGPs have remained elusive. Eight partially redundant Hyp-galactosyltransferases (named GALT2-GALT9) genes/enzymes are known to initiate Hyp-O-galactosylation for Hyp-arabinogalactan (AG) production in Arabidopsis thaliana. To assess the contributions of these Hyp-AGs to male reproductive function, we used a galt2galt5galt7galt8galt9 quintuple Hyp-GALT mutant for this study. Both anther size and pollen viability were compromised in the quintuple mutants. Defects in male gametogenesis were observed in later stages of maturing microspores after meiosis, accompanied by membrane blebbing and numerous lytic vacuoles. Cytological and ultramicroscopic observations revealed that pollen exine reticulate architecture and intine layer development were affected such that non-viable collapsed mature pollen grains were produced, which were devoid of cell content and nuclei, with virtually no intine. AGP immunolabeling demonstrated alterations in cell wall architecture of the anther, pollen grains, and pollen tube. Specifically, the LM2 monoclonal antibody (which recognized β-GlcA epitopes on AGPs) showed a weak signal for the endothecium, microspores, and pollen tube apex. Pollen tube tips also displayed excessive callose deposition. Interestingly, expression patterns of pollen-specific AGPs, namely AGP6, AGP11, AGP23, and AGP40, were determined to be higher in the quintuple mutants. Taken together, our data illustrate the importance of type-II AGs in male reproductive function for successful fertilization.

| S-EPMC9237623 | biostudies-literature

SKL1 Is Essential for Chloroplast Development in Arabidopsis.

Project description:The Arabidopsis shikimate kinase-like 1 (skl1-8) mutant is characterized by a pigment-defective phenotype. Although the related phenotypical defect mainly has been attributed to the blocking of chloroplast development, the molecular functions of SKL1 remain largely unknown. In this study, we combined multiple approaches to investigate the potential functions of SKL1. Results showed that the skl1-8 mutant exhibited an albino phenotype and had dramatically reduced chlorophyll content as a consequence of a single nuclear recessive gene mutation. Chemical complementation analysis indicated that SKL1 does not function as SK enzyme in the shikimate pathway. In addition, by chlorophyll fluorescence parameters and immunoblot analysis, the levels of photosynthetic proteins are substantially reduced. Moreover, by transcriptome analysis, specific groups of nuclear genes involved in photosynthesis, such as light-harvesting complex, pigment metabolism, carbon metabolism, and chloroplast gene expression, were down-regulated, whereas several defense and oxidative stress responsive genes were up-regulated in the skl1-8 mutant compared with the wide type. Furthermore, we found the expression of genes related to auxin transport and response was repressed in the skl1-8 mutant, probable suggesting that SKL1 is involved in auxin-related pathways during chloroplast development. Together, these results provide a useful reference for characterization of SKL1 function during chloroplast biogenesis and development.

| S-EPMC5826214 | biostudies-literature

Uncoupling of sustained MAMP receptor signaling from early outputs in an Arabidopsis endoplasmic reticulum glucosidase II allele.

Project description:Recognition of microbe-associated molecular patterns (MAMPs), conserved structures typical of a microbial class, triggers immune responses in eukaryotes. This is accompanied by a diverse set of physiological responses that are thought to enhance defense activity in plants. However, the extent and mechanisms by which MAMP-induced events contribute to host immunity are poorly understood. Here we reveal Arabidopsis priority in sweet life4 (psl4) and psl5 mutants that are insensitive to the bacterial elongation factor (EF)-Tu epitope elf18 but responsive to flagellin epitope flg22. PSL4 and PSL5, respectively, identify beta- and alpha-subunits of endoplasmic reticulum-resident glucosidase II, which is essential for stable accumulation and quality control of the elf18 receptor EFR but not the flg22 receptor FLS2. We notice that EFR signaling is partially and differentially impaired without a significant decrease of the receptor steady-state levels in 2 weakly dysfunctional gIIalpha alleles, designated psl5-1 and rsw3. Remarkably, rsw3 plants exhibit marked supersusceptibility against a virulent bacterial phytopathogen despite nearly intact coactivation of MAPKs, reactive oxygen species, ethylene biosynthesis, and callose deposition in response to elf18, demonstrating that these signaling outputs alone are insufficient to mount effective immunity. However, rsw3 plants fail to maintain high transcript levels of defense-promoting WRKY, PR1, and PR2 genes at late time points (4 to 24 h) after elf18 elicitation. This points to an unexpected separation between initial and sustained activation of EFR-mediated signaling in the absence of proper glucosidase II-mediated endoplasmic reticulum quality control. Our findings strongly suggest the importance of sustained MAMP receptor signaling as a key step in the establishment of robust immunity.

| S-EPMC2799704 | biostudies-literature

MNSs-mediated N-glycan processing is essential for auxin homeostasis in <i>Arabidopsis</i> roots during alkaline response.

Project description:Early steps in the endoplasmic reticulum (ER) lumen and cis-Golgi comprise trimming of N-glycans by class I α-mannosidases (MNSs) play crucial roles in root growth and stress response. Herein, we found that the root growth inhibition in the mns1 mns2 mns3 mutant was partially rescued under alkaline condition, and inhibitor treatment to disrupt auxin transport counteracted this alkaline-maintained root growth. Further study showed that indole-3-acetic acid (IAA) levels were undetectable in mns1 mns2 mns3 at normal condition and recovered at alkaline condition, which corroborate our N-glycopeptide profiling, from which N-glycopeptides related with IAA biosynthesis, amino acid conjugates hydrolysis, and response showed differential abundance between normal and alkaline conditions in mns1 mns2 mns3. Overall, our results linked the need for MNSs-mediated N-glycan processing in the ER and cis-Golgi with maintenance of auxin homeostasis and transport in Arabidopsis roots during the response to alkaline stress.

| S-EPMC9118167 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data