scholarly journals Demonstration that endoplasmic reticulum-associated degradation of glycoproteins can occur downstream of processing by endomannosidase

2011 ◽  
Vol 438 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Nikolay V. Kukushkin ◽  
Dominic S. Alonzi ◽  
Raymond A. Dwek ◽  
Terry D. Butters
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Chinese Hamster ◽  
Human Embryonic Kidney ◽  
Previous Evidence ◽  
Endoplasmic Reticulum Associated Degradation ◽  
Single Protein ◽  
Free Oligosaccharides ◽  
Intermediate Compartment ◽  
Functional Version

During quality control in the ER (endoplasmic reticulum), nascent glycoproteins are deglucosylated by ER glucosidases I and II. In the post-ER compartments, glycoprotein endo-α-mannosidase provides an alternative route for deglucosylation. Previous evidence suggests that endomannosidase non-selectively deglucosylates glycoproteins that escape quality control in the ER, facilitating secretion of aberrantly folded as well as normal glycoproteins. In the present study, we employed FOS (free oligosaccharides) released from degrading glycoproteins as biomarkers of ERAD (ER-associated degradation), allowing us to gain a global rather than single protein-centred view of ERAD. Glucosidase inhibition was used to discriminate between glucosidase- and endomannosidase-mediated ERAD pathways. Endomannosidase expression was manipulated in CHO (Chinese-hamster ovary)-K1 cells, naturally lacking a functional version of the enzyme, and HEK (human embryonic kidney)-293T cells. Endomannosidase was shown to decrease the levels of total FOS, suggesting decreased rates of ERAD. However, following pharmacological inhibition of ER glucosidases I and II, endomannosidase expression resulted in a partial switch between glucosylated FOS, released from ER-confined glycoproteins, to deglucosylated FOS, released from endomannosidase-processed glycoproteins transported from the Golgi/ERGIC (ER/Golgi intermediate compartment) to the ER. Using this approach, we have identified a previously unknown pathway of glycoprotein flow, undetectable by the commonly employed methods, in which secretory cargo is targeted back to the ER after being processed by endomannosidase.

scholarly journals Separate Roles and Different Routing of Calnexin and ERp57 in Endoplasmic Reticulum Quality Control Revealed by Interactions with Asialoglycoprotein Receptor Chains

2004 ◽  
Vol 15 (5) ◽  
pp. 2133-2142 ◽  
Author(s):  
Zehavit Frenkel ◽  
Marina Shenkman ◽  
Maria Kondratyev ◽  
Gerardo Z. Lederkremer
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Asialoglycoprotein Receptor ◽  
Low Concentration ◽  
Glucosidase Inhibitor ◽  
Endoplasmic Reticulum Associated Degradation ◽  
Endoplasmic Reticulum Quality Control ◽  
Intermediate Compartment ◽  
Thiol Oxidoreductase ◽  
Control Compartment

The thiol oxidoreductase endoplasmic reticulum (ER)p57 interacts with newly synthesized glycoproteins through ternary complexes with the chaperones/lectins calnexin or calreticulin. On proteasomal inhibition calnexin and calreticulin concentrate in the pericentriolar endoplasmic reticulum-derived quality control compartment that we recently described. Surprisingly, ERp57 remained in an endoplasmic reticulum pattern. Using asialoglycoprotein receptor H2a and H2b as models, we determined in pulse-chase experiments that both glycoproteins initially bind to calnexin and ERp57. However, H2b, which will exit to the Golgi, dissociated from calnexin and remained bound for a longer period to ERp57, whereas the opposite was true for the endoplasmic reticulum-associated degradation substrate H2a that will go to the endoplasmic reticulum-derived quality control compartment. At 15°C, ERp57 colocalized with H2b adjacent to an endoplasmic reticulum-Golgi intermediate compartment marker. Posttranslational inhibition of glucose excision prolonged association of H2a precursor to calnexin but not to ERp57. Preincubation with a low concentration (15 μg/ml) of the glucosidase inhibitor castanospermine prevented the association of H2a to ERp57 but not to calnexin. This low concentration of castanospermine accelerated the degradation of H2a, suggesting that ERp57 protects the glycoprotein from degradation and not calnexin. Our results suggest an early chaperone-mediated sorting event with calnexin being involved in the quality control retention of molecules bound for endoplasmic reticulum-associated degradation and ERp57 giving initial protection from degradation and later assisting the maturation of molecules that will exit to the Golgi.

scholarly journals Organizational Diversity among Distinct Glycoprotein Endoplasmic Reticulum-associated Degradation Programs

2002 ◽  
Vol 13 (8) ◽  
pp. 2639-2650 ◽  
Author(s):  
Christopher M. Cabral ◽  
Yan Liu ◽  
Kelley W. Moremen ◽  
Richard N. Sifers
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Pathway ◽  
Degradation Process ◽  
Secretory Protein ◽  
Human Embryonic Kidney ◽  
Apparent Lack ◽  
Human Embryonic Kidney Cells ◽  
Early Secretory Pathway ◽  
Endoplasmic Reticulum Associated Degradation ◽  
Pathway Function

Protein folding and quality control in the early secretory pathway function as posttranslational checkpoints in eukaryote gene expression. Herein, an aberrant form of the hepatic secretory protein α1-antitrypsin was stably expressed in a human embryonic kidney cell line to elucidate the mechanisms by which glycoprotein endoplasmic reticulum-associated degradation (GERAD) is administered in cells from higher eukaryotes. After biosynthesis, genetic variant PI Z underwent alternative phases of secretion and degradation, the latter of which was mediated by the proteasome. Degradation required release from calnexin- and asparagine-linked oligosaccharide modification by endoplasmic reticulum mannosidase I, the latter of which occurred as PI Z was bound to the molecular chaperone grp78/BiP. That a distinct GERAD program operates in human embryonic kidney cells was supported by the extent of PI Z secretion, apparent lack of polymerization, inability of calnexin to participate in the degradation process, and sequestration of the glycoprotein folding sensor UDP-glucose:glycoprotein glucosyltransferase in the Golgi complex. Because UDP-glucose:glycoprotein glucosyltransferase sustains calnexin binding, its altered distribution is consistent with a GERAD program that hinders the reentry of substrates into the calnexin cycle, allowing grp78/BiP to partner with a lectin, other than calnexin, in the recognition of a two-component GERAD signal to facilitate substrate recruitment. How the processing of a mutant protein, rather than the mutation itself, can contribute to disease pathogenesis, is discussed.

scholarly journals Free Oligosaccharides to Monitor Glycoprotein Endoplasmic Reticulum-associated Degradation inSaccharomyces cerevisiae

2010 ◽  
Vol 285 (16) ◽  
pp. 12390-12404 ◽  
Author(s):  
Hiroto Hirayama ◽  
Junichi Seino ◽  
Toshihiko Kitajima ◽  
Yoshifumi Jigami ◽  
Tadashi Suzuki
Keyword(s):  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Associated Degradation ◽  
Free Oligosaccharides

scholarly journals Reduction of HIV-1 Infectivity through Endoplasmic Reticulum-Associated Degradation-Mediated Env Depletion

2014 ◽  
Vol 89 (5) ◽  
pp. 2966-2971 ◽  
Author(s):  
Antonio Casini ◽  
Michele Olivieri ◽  
Lara Vecchi ◽  
Oscar R. Burrone ◽  
Anna Cereseto
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Secretory Pathway ◽  
Viral Production ◽  
Endoplasmic Reticulum Associated Degradation ◽  
Viral Particles ◽  
Erad Pathway ◽  
System Operating ◽  
Hiv 1 ◽  
Replicative Cycle

During the HIV-1 replicative cycle, the gp160 envelope is processed in the secretory pathway to mature into the gp41 and gp120 subunits. Misfolded proteins located within the endoplasmic reticulum (ER) are proteasomally degraded through the ER-associated degradation (ERAD) pathway, a quality control system operating in this compartment. Here, we exploited the ERAD pathway to induce the degradation of gp160 during viral production, thus leading to the release of gp120-depleted viral particles.

scholarly journals Investigating the role of ERAD on antibody processing in glycoengineered Saccharomyces cerevisiae

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Mari A Piirainen ◽  
Alexander D Frey
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Heavy Chain ◽  
Chain Molecules ◽  
Secretion Signal ◽  
Endoplasmic Reticulum Associated Degradation ◽  
Endoplasmic Reticulum Quality Control ◽  
Therapeutic Glycoproteins

ABSTRACT N-glycosylation plays an important role in the endoplasmic reticulum quality control (ERQC). N-glycan biosynthesis pathways have been engineered in yeasts and fungi to enable the production of therapeutic glycoproteins with human-compatible N-glycosylation, and some glycoengineering approaches alter the synthesis of the lipid-linked oligosaccharide (LLO). Because the effects of LLO engineering on ERQC are currently unknown, we characterized intracellular processing of IgG in glycoengineered Δalg3 Δalg11 Saccharomyces cerevisiae strain and analyzed how altered LLO structures affect endoplasmic reticulum-associated degradation (ERAD). Intracellular IgG light and heavy chain molecules expressed in Δalg3 Δalg11 strain are ERAD substrates and targeted to ERAD independently of Yos9p and Htm1p, whereas in the presence of ALG3 ERAD targeting is dependent on Yos9p but does not require Htm1p. Blocking of ERAD accumulated ER and post-Golgi forms of IgG and increased glycosylation of matα secretion signal but did not improve IgG secretion. Our results show ERAD targeting of a heterologous glycoprotein in yeast, and suggest that proteins in the ER can be targeted to ERAD via other mechanisms than the Htm1p-Yos9p-dependent route when the LLO biosynthesis is altered.

scholarly journals Bap31 Is an Itinerant Protein That Moves between the Peripheral Endoplasmic Reticulum (ER) and a Juxtanuclear Compartment Related to ER-associated Degradation

2008 ◽  
Vol 19 (5) ◽  
pp. 1825-1836 ◽  
Author(s):  
Yuichi Wakana ◽  
Sawako Takai ◽  
Ken-ichi Nakajima ◽  
Katsuko Tani ◽  
Akitsugu Yamamoto ◽  
...  
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Transmembrane Proteins ◽  
Transmembrane Domains ◽  
Er Quality Control ◽  
Transport Pathways ◽  
The Third ◽  
Intermediate Compartment ◽  
Er Export ◽  
Control Compartment

Certain endoplasmic reticulum (ER)-associated degradation (ERAD) substrates with transmembrane domains are segregated from other ER proteins and sorted into a juxtanuclear subcompartment, known as the ER quality control compartment. Bap31 is an ER protein with three transmembrane domains, and it is assumed to be a cargo receptor for ER export of some transmembrane proteins, especially those prone to ERAD. Here, we show that Bap31 is a component of the ER quality control compartment and that it moves between the peripheral ER and a juxtanuclear ER or ER-related compartment distinct from the conventional ER–Golgi intermediate compartment. The third and second transmembrane domains of Bap31 are principally responsible for the movement to and recycling from the juxtanuclear region, respectively. This cycling was blocked by depolymerization of microtubules and disruption of dynein–dynactin function. Overexpression of Sar1p and Arf1 mutants affected Bap31 cycling, suggesting that this cycling pathway is related to the conventional vesicular transport pathways.

scholarly journals Lys11- and Lys48-linked ubiquitin chains interact with p97 during endoplasmic-reticulum-associated degradation

2014 ◽  
Vol 459 (1) ◽  
pp. 205-216 ◽  
Author(s):  
Matthew Locke ◽  
Julia I. Toth ◽  
Matthew D. Petroski
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Protein Quality ◽  
Protein Quality Control ◽  
Endoplasmic Reticulum Membrane ◽  
Endoplasmic Reticulum Associated Degradation

This study provides evidence that p97 interacts with proteins modified with Lys11- and Lys48-linked ubiquitin chains at the endoplasmic reticulum membrane, suggesting roles for these signals in protein quality control.

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