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

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Tadashi Satoh ◽  
Takayasu Toshimori ◽  
Gengwei Yan ◽  
Takumi Yamaguchi ◽  
Koichi Kato
Keyword(s):  
Quality Control ◽  
Structural Basis ◽  
Glucosidase Ii ◽  
Glycoprotein Quality Control

scholarly journals Interaction mode between catalytic and regulatory subunits in glucosidase II involved in ER glycoprotein quality control

2016 ◽  
Vol 25 (11) ◽  
pp. 2095-2101 ◽  
Author(s):  
Tadashi Satoh ◽  
Takayasu Toshimori ◽  
Masanori Noda ◽  
Susumu Uchiyama ◽  
Koichi Kato
Keyword(s):  
Quality Control ◽  
Regulatory Subunits ◽  
Glucosidase Ii ◽  
Interaction Mode ◽  
Glycoprotein Quality Control

scholarly journals Structural basis for substrate recognition mechanism of ER glucosidase II

2014 ◽  
Vol 70 (a1) ◽  
pp. C300-C300
Author(s):  
Tadashi Satoh ◽  
Takayasu Toshimori ◽  
Takumi Yamaguchi ◽  
Zhu Tong ◽  
Koichi Kato
Keyword(s):  
Crystal Structure ◽  
Quality Control ◽  
Control System ◽  
Substrate Binding ◽  
Terminal Segment ◽  
Glycoside Hydrolases ◽  
Quality Control System ◽  
Structural Basis ◽  
Α Subunit ◽  
Glucosidase Ii

The endoplasmic reticulum (ER) possesses a sophisticated quality control system to proofread newly synthesized proteins. A series of N-linked oligosaccharide intermediates attached on the nascent proteins serves as specific tags for the quality control system. In this system, glucosidase II is involved in trimming of non-reducing terminal glucose residue of N-glycan intermediates. Glucosidase II consists of approximately 110 kDa catalytic α subunit (GIIα) and 60 kDa non-catalytic regulatory β subunit (GIIβ). It has been shown that GIIα alone can hydrolyze a small α-glycosidase model substrate (pNP-glucose), while it cannot catalyze deglucosylation of the N-linked oligosaccharide substrates unless it makes a complex with GIIβ. In this study, we determined the first crystal structure of GIIα in the absence and presence of its inhibitor 1-deoxynojirimycin at 1.6-Å resolution. The crystal structure revealed that GIIα has a characteristic segment at the N-terminus as compared with the cognate glycoside hydrolases (GH31). Interestingly, the N-terminal segment was accommodated on the substrate-binding pocket. Based on these results, we suggest that the N-terminal segment of GIIα undergoes structural rearrangement through interaction with GIIβ, thereby promoting the substrate-binding capacity for the N-linked oligosaccharide substrates.

scholarly journals Trypanosoma cruziCalreticulin Is a Lectin That Binds Monoglucosylated Oligosaccharides but Not Protein Moieties of Glycoproteins

1999 ◽  
Vol 10 (5) ◽  
pp. 1381-1394 ◽  
Author(s):  
Carlos Labriola ◽  
Juan J. Cazzulo ◽  
Armando J. Parodi
Keyword(s):  
Quality Control ◽  
Mammalian Cells ◽  
Protozoan Parasite ◽  
Glucosidase Ii ◽  
The Third ◽  
Oligosaccharide Processing ◽  
Encoding Gene ◽  
Higher Eukaryotes ◽  
Lysosomal Proteinase ◽  
Protein Moiety

Trypanosoma cruzi is a protozoan parasite that belongs to an early branch in evolution. Although it lacks several features of the pathway of protein N-glycosylation and oligosaccharide processing present in the endoplasmic reticulum of higher eukaryotes, it displays UDP-Glc:glycoprotein glucosyltransferase and glucosidase II activities. It is herewith reported that this protozoan also expresses a calreticulin-like molecule, the third component of the quality control of glycoprotein folding. No calnexin-encoding gene was detected. Recombinant T. cruzi calreticulin specifically recognized free monoglucosylated high-mannose-type oligosaccharides. Addition of anti-calreticulin serum to extracts obtained from cells pulse–chased with [35S]Met plus [35S]Cys immunoprecipitated two proteins that were identified as calreticulin and the lysosomal proteinase cruzipain (a major soluble glycoprotein). The latter but not the former protein disappeared from immunoprecipitates upon chasing cells. Contrary to what happens in mammalian cells, addition of the glucosidase II inhibitor 1-deoxynojirimycin promoted calreticulin–cruzipain interaction. This result is consistent with the known pathway of proteinN-glycosylation and oligosaccharide processing occurring in T. cruzi. A treatment of the calreticulin-cruzipain complexes with endo-β-N-acetylglucosaminidase H either before or after addition of anti-calreticulin serum completely disrupted calreticulin–cruzipain interaction. In addition, mature monoglucosylated but not unglucosylated cruzipain isolated from lysosomes was found to interact with recombinant calreticulin. It was concluded that the quality control of glycoprotein folding appeared early in evolution, and that T. cruzi calreticulin binds monoglucosylated oligosaccharides but not the protein moiety of cruzipain. Furthermore, evidence is presented indicating that glucosyltransferase glucosylated cruzipain at its last folding stages.

scholarly journals Structural basis for bacterial ribosome quality control

2020 ◽  
Author(s):  
Caillan Crowe-McAuliffe ◽  
Hiraku Takada ◽  
Victoriia Murina ◽  
Christine Polte ◽  
Sergo Kasvandik ◽  
...  
Keyword(s):  
Quality Control ◽  
Bacillus Subtilis ◽  
Single Particle ◽  
Ex Vivo ◽  
Large Subunit ◽  
Small Subunit ◽  
Structural Basis ◽  
Bacterial Ribosome

SummaryIn all branches of life, stalled translation intermediates are recognized and processed by ribosome-associated quality-control (RQC) pathways. RQC begins with splitting of stalled ribosomes, leaving an unfinished polypeptide still attached to the large subunit. Ancient and conserved NEMF family RQC proteins target these incomplete proteins for degradation by the addition of C-terminal ‘tails.’ How such tailing can occur without the regular suite of translational components is, however, unclear. Using ex vivo single-particle cryo-EM, we show that C-terminal tailing in Bacillus subtilis is mediated by NEMF protein RqcH in concert with YabO, a protein homologous to, yet distinct from, Hsp15. Our structures reveal how these factors mediate tRNA movement across the ribosomal 50S subunit to synthesize polypeptides in the absence of mRNA or the small subunit.

scholarly journals Stepwise maturation of the peptidyl transferase region of human mitoribosomes

2021 ◽  
Author(s):  
Tea Lenarcic ◽  
Mateusz Jaskolowski ◽  
Marc Leibundgut ◽  
Alain Scaiola ◽  
Tanja Schoenhut ◽  
...  
Keyword(s):  
Quality Control ◽  
16S Rrna ◽  
Active Site ◽  
Critical Role ◽  
Ribosomal Subunit ◽  
Structural Basis ◽  
Ribosome Assembly ◽  
Peptidyl Transferase ◽  
Mitochondrial Ribosomes ◽  
Mitochondrial Ribosome

Mitochondrial ribosomes are specialized for the synthesis of membrane proteins responsible for oxidative phosphorylation. Mammalian mitoribosomes diverged considerably from the ancestral bacterial ribosomes and feature dramatically reduced ribosomal RNAs. Structural basis of the mammalian mitochondrial ribosome assembly is currently not understood. Here we present eight distinct assembly intermediates of the human large mitoribosomal subunit involving 7 assembly factors. We discover that NSUN4-MTERF4 dimer plays a critical role in the process by stabilizing the 16S rRNA in a conformation that exposes the functionally important regions of rRNA for modification by MRM2 methyltransferase and quality control interactions with a conserved mitochondrial GTPase MTG2 that contacts the sarcin ricin loop and the immature active site. The successive action of these factors leads to the formation of the peptidyl transferase active site of the mitoribosome and the folding of the surrounding rRNA regions responsible for interactions with tRNAs and the small ribosomal subunit.

scholarly journals Malectin Participates in a Backup Glycoprotein Quality Control Pathway in the Mammalian ER

PLoS ONE ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. e16304 ◽  
Author(s):  
Carmela Galli ◽  
Riccardo Bernasconi ◽  
Tatiana Soldà ◽  
Verena Calanca ◽  
Maurizio Molinari
Keyword(s):  
Quality Control ◽  
Glycoprotein Quality Control

scholarly journals UDP-GlC:glycoprotein glucosyltransferase-glucosidase II, the ying-yang of the ER quality control

2010 ◽  
Vol 21 (5) ◽  
pp. 491-499 ◽  
Author(s):  
Cecilia D’Alessio ◽  
Julio J. Caramelo ◽  
Armando J. Parodi
Keyword(s):  
Quality Control ◽  
Er Quality Control ◽  
Glucosidase Ii

scholarly journals Structural basis for dimerization quality control

Nature ◽  
2020 ◽  
Vol 586 (7829) ◽  
pp. 452-456 ◽  
Author(s):  
Elijah L. Mena ◽  
Predrag Jevtić ◽  
Basil J. Greber ◽  
Christine L. Gee ◽  
Brandon G. Lew ◽  
...  
Keyword(s):  
Quality Control ◽  
Structural Basis
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