1
|
Fujihira H, Sato K, Nishiuchi Y, Murase T, Matsuda Y, Yoshida Y, Kamei T, Suzuki T. ELISA-based highly sensitive assay system for the detection of endogenous NGLY1 activity. Biochem Biophys Res Commun 2024; 710:149826. [PMID: 38581946 DOI: 10.1016/j.bbrc.2024.149826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 03/21/2024] [Accepted: 03/24/2024] [Indexed: 04/08/2024]
Abstract
Cytosolic peptide:N-glycanase (NGLY1, PNGase) is an enzyme that cleaves N-glycans from misfolded glycoproteins. In 2012, a human genetic disorder, NGLY1 deficiency, was first reported to be caused by mutations of the NGLY1 gene. Since then, there has been rapid progresses on NGLY1 biology, and gene therapy has been proposed as a promising therapeutic option for NGLY1 deficiency. While a plasma/urine biomarker has also been developed for this disease, detection of NGLY1 activity could be another viable option for early diagnosis of NGLY1 deficiency. Thus far, several in vitro and in cellulo NGLY1 assays have been reported, but those assay systems have several issues that must be addressed in order to develop an assay system compatible for routine clinical examination. Here, we show a facile, highly sensitive in vitro assay system that could be used to detect NGLY1 activity by utilizing its sequence editing function, i.e. conversion of glycosylated Asn into Asp, followed by a detection of newly generated epitope (HA)-tag by anti-HA antibody. Using this ELISA-based assay, we detected endogenous NGLY1 activity in as little as 2 μg of crude extract, which is the equivalent of 5 × 103 cells. Our system also detects NGLY1 activity from cells with compromised NGLY1 activity, such as iPS cells from patient samples. This assay system could be applied in future clinical examinations to achieve an early diagnosis of NGLY1 deficiency.
Collapse
Affiliation(s)
- Haruhiko Fujihira
- Glycometabolic Biochemistry Laboratory, Cluster for Pioneering Research, RIKEN, Saitama, 351-0198, Japan; Division of Glycobiologics, Juntendo University Graduate School of Medicine, Tokyo, 113-8421, Japan
| | - Keiko Sato
- Glycometabolic Biochemistry Laboratory, Cluster for Pioneering Research, RIKEN, Saitama, 351-0198, Japan
| | | | | | | | - Yukiko Yoshida
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, Tokyo, 156-8506, Japan
| | - Takayuki Kamei
- Global Advanced Platform, Takeda Pharmaceutical Co. Ltd., Kanagawa, 251-8555, Japan; NGLY1 Deficiency Project, T-CiRA Joint Program, Kanagawa, 251-8555, Japan
| | - Tadashi Suzuki
- Glycometabolic Biochemistry Laboratory, Cluster for Pioneering Research, RIKEN, Saitama, 351-0198, Japan; NGLY1 Deficiency Project, T-CiRA Joint Program, Kanagawa, 251-8555, Japan.
| |
Collapse
|
2
|
Hirayama H, Suzuki T. Assay for the peptide:N-glycanase/NGLY1 and disease-specific biomarkers for diagnosing NGLY1 deficiency. J Biochem 2021; 171:169-176. [PMID: 34791337 DOI: 10.1093/jb/mvab127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/11/2021] [Indexed: 11/13/2022] Open
Abstract
Cytosolic peptide:N-glycanase (NGLY1 in mammals), a highly conserved enzyme in eukaryotes, catalyzes the deglycosylation of N-glycans that are attached to glycopeptide/glycoproteins. In 2012, an autosomal recessive disorder related to the NGLY1 gene, which was referred to as NGLY1 deficiency, was reported. Since then, more than 100 patients have been identified. Patients with this disease exhibit various symptoms, including various motor deficits and other neurological problems. Effective therapeutic treatments for this disease, however, have not been established. Most recently, it was demonstrated that the intracerebroventricular administration of an adeno-associated virus 9 vector expressing human NGLY1 during the weaning period allowed some motor functions to be recovered in Ngly1-/- rats. This observation led us to hypothesize that a therapeutic intervention for improving these motor deficits or other neurological symptoms found in the patients might be possible. To achieve this, it is critical to establish robust and facile methods for assaying NGLY1 activity in biological samples, for the early diagnosis and evaluation of the therapeutic efficacy for the treatment of NGLY1 deficiency. In this mini-review, we summarize progress made in the development of various assay methods for NGLY1 activity, as well as a recent progress in the identification of NGLY1 deficiency-specific biomarkers.
Collapse
Affiliation(s)
- Hiroto Hirayama
- Glycometabolic Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, RIKEN, Japan.,Takeda-CiRA Joint Program (T-CiRA), Kanagawa, Japan
| | - Tadashi Suzuki
- Glycometabolic Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, RIKEN, Japan.,Takeda-CiRA Joint Program (T-CiRA), Kanagawa, Japan
| |
Collapse
|
3
|
Hirayama H, Tachida Y, Seino J, Suzuki T. A method for assaying peptide: N-glycanase/N-Glycanase 1 activities in crude extracts using an N-glycosylated cyclopeptide. Glycobiology 2021; 32:110-122. [PMID: 34939090 PMCID: PMC8934141 DOI: 10.1093/glycob/cwab115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/09/2021] [Accepted: 10/31/2021] [Indexed: 11/13/2022] Open
Abstract
Cytosolic peptide: N-glycanase (PNGase; NGLY1), an enzyme responsible for de-glycosylation of N-glycans on glycoproteins, is known to play pivotal roles in a variety of biological processes. In 2012, NGLY1 deficiency, a rare genetic disorder, was reported and since then, more than 100 patients have now been identified worldwide. Patients with this disease exhibit several common symptoms that are caused by the dysfunction of NGLY1. However, correlation between the severity of patient symptoms and the extent of the reduction in NGLY1 activity in these patients remains to be clarified, mainly due to the absence of a facile quantitative assay system for this enzyme, especially in a crude extract as an enzyme source. In this study, a quantitative, non-radioisotope (RI)-based assay method for measuring recombinant NGLY1 activity was established using a BODIPY-labeled asialoglycopeptide (BODIPY-ASGP) derived from hen eggs. With this assay, the activities of 27 recombinant NGLY1 mutants that are associated with the deficiency were examined. It was found that the activities of 3 (R469X, R458fs, and H494fs) out of the 27 recombinant mutant proteins were 30-70 percent of the activities of wild-type NGLY1. We further developed a method for measuring endogenous NGLY1 activity in crude extracts derived from cultured cells, patients' fibroblasts, iPS cells or peripheral blood mononuclear cells (PBMCs), using a glycosylated cyclopeptide (GCP) that exhibited resistance to the endogenous proteases in the extract. Our methods will not only provide new insights into the molecular mechanism responsible for this disease but also promises to be applicable for its diagnosis.
Collapse
Affiliation(s)
- Hiroto Hirayama
- Glycometabolic Biochemistry Laboratory, RIKEN Cluster for Pioneering Research (CPR), Riken, Japan.,Takeda-CiRA Joint Program (T-CiRA), Kanagawa, Japan
| | - Yuriko Tachida
- Glycometabolic Biochemistry Laboratory, RIKEN Cluster for Pioneering Research (CPR), Riken, Japan.,Takeda-CiRA Joint Program (T-CiRA), Kanagawa, Japan
| | - Junichi Seino
- Glycometabolic Biochemistry Laboratory, RIKEN Cluster for Pioneering Research (CPR), Riken, Japan
| | - Tadashi Suzuki
- Glycometabolic Biochemistry Laboratory, RIKEN Cluster for Pioneering Research (CPR), Riken, Japan.,Takeda-CiRA Joint Program (T-CiRA), Kanagawa, Japan
| |
Collapse
|
4
|
Abstract
Folding of proteins is essential so that they can exert their functions. For proteins that transit the secretory pathway, folding occurs in the endoplasmic reticulum (ER) and various chaperone systems assist in acquiring their correct folding/subunit formation. N-glycosylation is one of the most conserved posttranslational modification for proteins, and in eukaryotes it occurs in the ER. Consequently, eukaryotic cells have developed various systems that utilize N-glycans to dictate and assist protein folding, or if they consistently fail to fold properly, to destroy proteins for quality control and the maintenance of homeostasis of proteins in the ER.
Collapse
|
5
|
Derlin-3 Is Required for Changes in ERAD Complex Formation under ER Stress. Int J Mol Sci 2020; 21:ijms21176146. [PMID: 32858914 PMCID: PMC7504720 DOI: 10.3390/ijms21176146] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 08/18/2020] [Accepted: 08/24/2020] [Indexed: 12/17/2022] Open
Abstract
Endoplasmic reticulum (ER)-associated protein degradation (ERAD) is a quality control system that induces the degradation of ER terminally misfolded proteins. The ERAD system consists of complexes of multiple ER membrane-associated and luminal proteins that function cooperatively. We aimed to reveal the role of Derlin-3 in the ERAD system using the liver, pancreas, and kidney obtained from different mouse genotypes. We performed coimmunoprecipitation and sucrose density gradient centrifugation to unravel the dynamic nature of ERAD complexes. We observed that Derlin-3 is exclusively expressed in the pancreas, and its deficiency leads to the destabilization of Herp and accumulation of ERAD substrates. Under normal conditions, Complex-1a predominantly contains Herp, Derlin-2, HRD1, and SEL1L, and under ER stress, Complex-1b contains Herp, Derlin-3 (instead of Derlin-2), HRD1, and SEL1L. Complex-2 is upregulated under ER stress and contains Derlin-1, Derlin-2, p97, and VIMP. Derlin-3 deficiency suppresses the transition of Derlin-2 from Complex-1a to Complex-2 under ER stress. In the pancreas, Derlin-3 deficiency blocks Derlin-2 transition. In conclusion, the composition of ERAD complexes is tissue-specific and changes in response to ER stress in a Derlin-3-dependent manner. Derlin-3 may play a key role in changing ERAD complex compositions to overcome ER stress.
Collapse
|
6
|
Mueller WF, Jakob P, Sun H, Clauder-Münster S, Ghidelli-Disse S, Ordonez D, Boesche M, Bantscheff M, Collier P, Haase B, Benes V, Paulsen M, Sehr P, Lewis J, Drewes G, Steinmetz LM. Loss of N-Glycanase 1 Alters Transcriptional and Translational Regulation in K562 Cell Lines. G3 (BETHESDA, MD.) 2020; 10:1585-1597. [PMID: 32265286 PMCID: PMC7202010 DOI: 10.1534/g3.119.401031] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/01/2020] [Indexed: 12/12/2022]
Abstract
N-Glycanase 1 (NGLY1) deficiency is an ultra-rare, complex and devastating neuromuscular disease. Patients display multi-organ symptoms including developmental delays, movement disorders, seizures, constipation and lack of tear production. NGLY1 is a deglycosylating protein involved in the degradation of misfolded proteins retrotranslocated from the endoplasmic reticulum (ER). NGLY1-deficient cells have been reported to exhibit decreased deglycosylation activity and an increased sensitivity to proteasome inhibitors. We show that the loss of NGLY1 causes substantial changes in the RNA and protein landscape of K562 cells and results in downregulation of proteasomal subunits, consistent with its processing of the transcription factor NFE2L1. We employed the CMap database to predict compounds that can modulate NGLY1 activity. Utilizing our robust K562 screening system, we demonstrate that the compound NVP-BEZ235 (Dactosilib) promotes degradation of NGLY1-dependent substrates, concurrent with increased autophagic flux, suggesting that stimulating autophagy may assist in clearing aberrant substrates during NGLY1 deficiency.
Collapse
Affiliation(s)
- William F Mueller
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Petra Jakob
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Han Sun
- Stanford University, CA, 94305
| | - Sandra Clauder-Münster
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Sonja Ghidelli-Disse
- Cellzome GmbH, a GlaxoSmithKline Company, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Diana Ordonez
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Markus Boesche
- Cellzome GmbH, a GlaxoSmithKline Company, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Marcus Bantscheff
- Cellzome GmbH, a GlaxoSmithKline Company, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Paul Collier
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Bettina Haase
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Vladimir Benes
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Malte Paulsen
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Peter Sehr
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Joe Lewis
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Gerard Drewes
- Cellzome GmbH, a GlaxoSmithKline Company, Meyerhofstrasse 1, Heidelberg, Germany, 69117
| | - Lars M Steinmetz
- European Molecular Biology Labs, Genome Biology Unit, Heidelberg, Germany, Meyerhofstrasse 1, Heidelberg, Germany, 69117
- Stanford University, CA, 94305
| |
Collapse
|
7
|
Huang C, Suzuki T. The occurrence of nonglycosylated forms of
N
‐glycoprotein upon proteasome inhibition does not confirm cytosolic deglycosylation. FEBS Lett 2020; 594:1433-1442. [DOI: 10.1002/1873-3468.13734] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/20/2019] [Accepted: 01/06/2020] [Indexed: 11/07/2022]
Affiliation(s)
- Chengcheng Huang
- Glycometabolic Biochemistry Laboratory RIKEN Cluster for Pioneering Research Wako Japan
| | - Tadashi Suzuki
- Glycometabolic Biochemistry Laboratory RIKEN Cluster for Pioneering Research Wako Japan
| |
Collapse
|
8
|
Donczo B, Kiraly G, Guttman A. Effect of the elapsed time between sampling and formalin fixation on the
N
‐glycosylation profile of mouse tissue specimens. Electrophoresis 2019; 40:3057-3061. [DOI: 10.1002/elps.201900109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 07/22/2019] [Accepted: 09/13/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Boglarka Donczo
- Horváth Csaba Laboratory of Bioseparation Sciences, Research Center for Molecular Medicine, Faculty of MedicineUniversity of Debrecen Debrecen Hungary
| | - Gabor Kiraly
- Department of Biotechnology and MicrobiologyUniversity of Debrecen Hungary
| | - Andras Guttman
- Horváth Csaba Laboratory of Bioseparation Sciences, Research Center for Molecular Medicine, Faculty of MedicineUniversity of Debrecen Debrecen Hungary
- MTA‐PE Translational Glycomics Research Group, Research Institute for Biomolecular and Chemical EngineeringUniversity of Pannonia Veszprem Hungary
| |
Collapse
|
9
|
Identification of PNGase-dependent ERAD substrates in Saccharomyces cerevisiae. Biochem J 2016; 473:3001-12. [DOI: 10.1042/bcj20160453] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 07/18/2016] [Indexed: 12/24/2022]
Abstract
Endoplasmic reticulum (ER)-associated degradation (ERAD) is a proteolytic pathway for handling misfolded or improperly assembled proteins that are synthesized in the ER. Cytoplasmic peptide:N-glycanase (PNGase) is a deglycosylating enzyme that cleaves N-glycans that are attached to ERAD substrates. While the critical roles of N-glycans in monitoring the folding status of carrier proteins in the ER lumen are relatively well understood, the physiological role of PNGase-mediated deglycosylation in the cytosol remained poorly understood. We report herein the identification of endogenous substrates for the cytoplasmic PNGase in Saccharomyces cerevisiae. Using an isotope-coded glycosylation site-specific tagging (IGOT) method-based LC/MS analysis, 11 glycoproteins were specifically detected in the cytosol of PNGase-deletion cells (png1Δ). Among these molecules, at least five glycoproteins were clearly identified as ERAD substrates in vivo. Moreover, four out of the five proteins were found to be either deglycosylated by PNGase in vivo or the overall degradation was delayed in a png1Δ mutant. Our results clearly indicate that the IGOT method promises to be a powerful tool for the identification of endogenous substrates for the cytoplasmic PNGase.
Collapse
|
10
|
Hirayama H, Hosomi A, Suzuki T. Physiological and molecular functions of the cytosolic peptide:N-glycanase. Semin Cell Dev Biol 2015; 41:110-20. [DOI: 10.1016/j.semcdb.2014.11.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 11/25/2014] [Accepted: 11/26/2014] [Indexed: 01/04/2023]
|
11
|
Endo-β-N-acetylglucosaminidase forms N-GlcNAc protein aggregates during ER-associated degradation in Ngly1-defective cells. Proc Natl Acad Sci U S A 2015; 112:1398-403. [PMID: 25605922 DOI: 10.1073/pnas.1414593112] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cytoplasmic peptide:N-glycanase (PNGase; Ngly1 in mice) is a deglycosylating enzyme involved in the endoplasmic reticulum (ER)-associated degradation (ERAD) process. The precise role of Ngly1 in the ERAD process, however, remains unclear in mammals. The findings reported herein, using mouse embryonic fibroblast (MEF) cells, that the ablation of Ngly1 causes dysregulation of the ERAD process. Interestingly, not only delayed degradation but also the deglycosylation of a misfolded glycoprotein was observed in Ngly1(-/-) MEF cells. The unconventional deglycosylation reaction was found to be catalyzed by the cytosolic endo-β-N-acetylglucosaminidase (ENGase), generating aggregation-prone N-GlcNAc proteins. The ERAD dysregulation in cells lacking Ngly1 was restored by the additional knockout of ENGase gene. Thus, our study underscores the functional importance of Ngly1 in the ERAD process and provides a potential mechanism underlying the phenotypic consequences of a newly emerging genetic disorder caused by mutation of the human NGLY1 gene.
Collapse
|
12
|
Hosomi A, Suzuki T. Cytoplasmic peptide:N-glycanase cleaves N-glycans on a carboxypeptidase Y mutant during ERAD in Saccharomyces cerevisiae. Biochim Biophys Acta Gen Subj 2014; 1850:612-9. [PMID: 25497214 DOI: 10.1016/j.bbagen.2014.12.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 11/07/2014] [Accepted: 12/04/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Endoplasmic reticulum (ER)-associated degradation (ERAD) is a pathway by which misfolded or improperly assembled proteins in the ER are directed to degradation. The cytoplasmic peptide:N-glycanase (PNGase) is a deglycosylating enzyme that cleaves N-glycans from misfolded glycoproteins during the ERAD process. The mutant form of yeast carboxypeptidase Y (CPY*) is an ERAD model substrate that has been extensively studied in yeast. While a delay in the degradation of CPY* in yeast cells lacking the cytoplasmic PNGase (Png1 in yeast) was evident, the in vivo action of PNGase on CPY* has not been detected. METHODS We constructed new ERAD substrates derived from CPY*, bearing epitope tags at both N- and C-termini and examined the degradation intermediates observed in yeast cells with compromised proteasome activity. RESULTS The occurrence of the PNGase-mediated deglycosylation of intact CPY* and its degradation intermediates was evident. A major endoproteolytic reaction on CPY* appears to occur between amino acid 400 and 404. CONCLUSIONS The findings reported herein clearly indicate that PNGase indeed releases N-glycans from CPY* during the ERAD process in vivo. GENERAL SIGNIFICANCE This report implies that the PNGase-mediated deglycosylation during the ERAD process may occur more abundantly than currently envisaged.
Collapse
Affiliation(s)
- Akira Hosomi
- Glycometabolome Team, RIKEN-Max Planck Institute Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tadashi Suzuki
- Glycometabolome Team, RIKEN-Max Planck Institute Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| |
Collapse
|
13
|
Yan Q, Li XP, Tumer NE. Wild type RTA and less toxic variants have distinct requirements for Png1 for their depurination activity and toxicity in Saccharomyces cerevisiae. PLoS One 2014; 9:e113719. [PMID: 25436896 PMCID: PMC4250064 DOI: 10.1371/journal.pone.0113719] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 10/30/2014] [Indexed: 01/29/2023] Open
Abstract
Ricin A chain (RTA) undergoes retrograde trafficking and is postulated to use components of the endoplasmic reticulum (ER) associated degradation (ERAD) pathway to enter the cytosol to depurinate ribosomes. However, it is not known how RTA evades degradation by the proteasome after entry into the cytosol. We observed two distinct trafficking patterns among the precursor forms of wild type RTA and nontoxic variants tagged with enhanced green fluorescent protein (EGFP) at their C-termini in yeast. One group, which included wild type RTA, underwent ER-to-vacuole transport, while another group, which included the G83D variant, formed aggregates in the ER and was not transported to the vacuole. Peptide: N-glycanase (Png1), which catalyzes degradation of unfolded glycoproteins in the ERAD pathway affected depurination activity and toxicity of wild type RTA and G83D variant differently. PreG83D variant was deglycosylated by Png1 on the ER membrane, which reduced its depurination activity and toxicity by promoting its degradation. In contrast, wild type preRTA was deglycosylated by the free pool of Png1 in the cytosol, which increased its depurination activity, possibly by preventing its degradation. These results indicate that wild type RTA has a distinct requirement for Png1 compared to the G83D variant and is deglycosylated by Png1 in the cytosol as a possible strategy to avoid degradation by the ERAD pathway to reach the ribosome.
Collapse
Affiliation(s)
- Qing Yan
- Department of Plant Biology and Pathology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Xiao-Ping Li
- Department of Plant Biology and Pathology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Nilgun E. Tumer
- Department of Plant Biology and Pathology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, United States of America
- * E-mail:
| |
Collapse
|
14
|
Suzuki T. The cytoplasmic peptide:N-glycanase (Ngly1)--basic science encounters a human genetic disorder. J Biochem 2014; 157:23-34. [DOI: 10.1093/jb/mvu068] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
15
|
Enns GM, Shashi V, Bainbridge M, Gambello MJ, Zahir FR, Bast T, Crimian R, Schoch K, Platt J, Cox R, Bernstein JA, Scavina M, Walter RS, Bibb A, Jones M, Hegde M, Graham BH, Need AC, Oviedo A, Schaaf CP, Boyle S, Butte AJ, Chen R, Chen R, Clark MJ, Haraksingh R, Cowan TM, He P, Langlois S, Zoghbi HY, Snyder M, Gibbs RA, Freeze HH, Goldstein DB. Mutations in NGLY1 cause an inherited disorder of the endoplasmic reticulum-associated degradation pathway. Genet Med 2014; 16:751-8. [PMID: 24651605 DOI: 10.1038/gim.2014.22] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 02/09/2014] [Indexed: 12/13/2022] Open
Abstract
PURPOSE The endoplasmic reticulum-associated degradation pathway is responsible for the translocation of misfolded proteins across the endoplasmic reticulum membrane into the cytosol for subsequent degradation by the proteasome. To define the phenotype associated with a novel inherited disorder of cytosolic endoplasmic reticulum-associated degradation pathway dysfunction, we studied a series of eight patients with deficiency of N-glycanase 1. METHODS Whole-genome, whole-exome, or standard Sanger sequencing techniques were employed. Retrospective chart reviews were performed in order to obtain clinical data. RESULTS All patients had global developmental delay, a movement disorder, and hypotonia. Other common findings included hypolacrima or alacrima (7/8), elevated liver transaminases (6/7), microcephaly (6/8), diminished reflexes (6/8), hepatocyte cytoplasmic storage material or vacuolization (5/6), and seizures (4/8). The nonsense mutation c.1201A>T (p.R401X) was the most common deleterious allele. CONCLUSION NGLY1 deficiency is a novel autosomal recessive disorder of the endoplasmic reticulum-associated degradation pathway associated with neurological dysfunction, abnormal tear production, and liver disease. The majority of patients detected to date carry a specific nonsense mutation that appears to be associated with severe disease. The phenotypic spectrum is likely to enlarge as cases with a broader range of mutations are detected.
Collapse
Affiliation(s)
- Gregory M Enns
- Department of Pediatrics, Division of Medical Genetics, Lucile Packard Children's Hospital, Stanford University, Stanford, California, USA
| | - Vandana Shashi
- Department of Pediatrics, Division of Medical Genetics, Duke University, Durham, North Carolina, USA
| | - Matthew Bainbridge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Michael J Gambello
- Department of Human Genetics, Division of Medical Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Farah R Zahir
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Rebecca Crimian
- Department of Pediatrics, Division of Medical Genetics, Duke University, Durham, North Carolina, USA
| | - Kelly Schoch
- Department of Pediatrics, Division of Medical Genetics, Duke University, Durham, North Carolina, USA
| | - Julia Platt
- Department of Pediatrics, Division of Medical Genetics, Lucile Packard Children's Hospital, Stanford University, Stanford, California, USA
| | - Rachel Cox
- Department of Pediatrics, Division of Medical Genetics, Lucile Packard Children's Hospital, Stanford University, Stanford, California, USA
| | - Jonathan A Bernstein
- Department of Pediatrics, Division of Medical Genetics, Lucile Packard Children's Hospital, Stanford University, Stanford, California, USA
| | - Mena Scavina
- Division of Pediatric Neurology, Department of Pediatrics, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware, USA
| | - Rhonda S Walter
- Division of Developmental Medicine, Department of Pediatrics, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware, USA
| | - Audrey Bibb
- Department of Human Genetics, Division of Medical Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Melanie Jones
- Department of Human Genetics, Division of Medical Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Madhuri Hegde
- Department of Human Genetics, Division of Medical Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Anna C Need
- Department of Medicine, Imperial College, London, UK
| | - Angelica Oviedo
- Department of Pathology and Laboratory Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Christian P Schaaf
- 1] Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA [2] Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, USA
| | - Sean Boyle
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Atul J Butte
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Rui Chen
- Department of Genetics, Stanford University School of Medicine, Stanford, California, USA
| | - Rong Chen
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Michael J Clark
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Rajini Haraksingh
- Department of Genetics, Stanford University, Stanford, California, USA
| | | | - Tina M Cowan
- Department of Pathology, Stanford University, Stanford, California, USA
| | - Ping He
- Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Sylvie Langlois
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Huda Y Zoghbi
- 1] Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA [2] Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, USA [3] Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, USA
| | - Michael Snyder
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Richard A Gibbs
- 1] Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA [2] Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Hudson H Freeze
- Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - David B Goldstein
- 1] Center for Human Genome Variation and Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA [2] Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| |
Collapse
|
16
|
Masahara-Negishi Y, Hosomi A, Della Mea M, Serafini-Fracassini D, Suzuki T. A plant peptide: N-glycanase orthologue facilitates glycoprotein ER-associated degradation in yeast. Biochim Biophys Acta Gen Subj 2012; 1820:1457-62. [PMID: 22659524 DOI: 10.1016/j.bbagen.2012.05.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 05/14/2012] [Accepted: 05/21/2012] [Indexed: 11/16/2022]
Abstract
BACKGROUND The cytoplasmic peptide:N-glycanase (PNGase) is a deglycosylating enzyme involved in the ER-associated degradation (ERAD) process, while ERAD-independent activities are also reported. Previous biochemical analyses indicated that the cytoplasmic PNGase orthologue in Arabidopsis thaliana (AtPNG1) can function as not only PNGase but also transglutaminase, while its in vivo function remained unclarified. METHODS AtPNG1 was expressed in Saccharomyces cerevisiae and its in vivo role on PNGase-dependent ERAD pathway was examined. RESULTS AtPNG1 could facilitate the ERAD through its deglycosylation activity. Moreover, a catalytic mutant of AtPNG1 (AtPNG1(C251A)) was found to significantly impair the ERAD process. This result was found to be N-glycan-dependent, as the AtPNG(C251A) did not affect the stability of the non-glycosylated RTA∆ (ricin A chain non-toxic mutant). Tight interaction between AtPNG1(C251A) and the RTA∆ was confirmed by co-immunoprecipitation analysis. CONCLUSION The plant PNGase facilitates ERAD through its deglycosylation activity, while the catalytic mutant of AtPNG1 impair glycoprotein ERAD by binding to N-glycans on the ERAD substrates. GENERAL SIGNIFICANCE Our studies underscore the functional importance of a plant PNGase orthologue as a deglycosylating enzyme involved in the ERAD.
Collapse
Affiliation(s)
- Yuki Masahara-Negishi
- Glycometabolome Team, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | | | | | | | | |
Collapse
|
17
|
Abstract
The endoplasmic reticulum (ER) uses an elaborate surveillance system called the ER quality control (ERQC) system. The ERQC facilitates folding and modification of secretory and membrane proteins and eliminates terminally misfolded polypeptides through ER-associated degradation (ERAD) or autophagic degradation. This mechanism of ER protein surveillance is closely linked to redox and calcium homeostasis in the ER, whose balance is presumed to be regulated by a specific cellular compartment. The potential to modulate proteostasis and metabolism with chemical compounds or targeted siRNAs may offer an ideal option for the treatment of disease.
Collapse
|
18
|
Kato A, Wang L, Ishii K, Seino J, Asano N, Suzuki T. Calystegine B3 as a specific inhibitor for cytoplasmic alpha-mannosidase, Man2C1. J Biochem 2011; 149:415-22. [PMID: 21217149 DOI: 10.1093/jb/mvq153] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cytoplasmic α-mannosidase (Man2C1) has been implicated in non-lysosomal catabolism of free oligosaccharides derived from N-linked glycans accumulated in the cytosol. Suppression of Man2C1 expression reportedly induces apoptosis in various cell lines, but its molecular mechanism remains unclear. Development of a specific inhibitor for Man2C1 is critical to understanding its biological significance. In this study, we identified a plant-derived alkaloid, calystegine B(3), as a potent specific inhibitor for Man2C1 activity. Biochemical enzyme assay revealed that calystegine B(3) was a highly specific inhibitor for Man2C1 among various α-mannosidases prepared from rat liver. Consistent with this in vitro result, an in vivo experiment also showed that treatment of mammalian-derived cultured cells with this compound resulted in drastic change in both structure and quantity of free oligosaccharides in the cytosol, whereas no apparent change was seen in cell-surface oligosaccharides. Calystegine B(3) could thus serve as a potent tool for the development of a highly specific in vivo inhibitor for Man2C1.
Collapse
Affiliation(s)
- Atsushi Kato
- Department of Hospital Pharmacy, University of Toyama, Toyama 930-0194, Japan
| | | | | | | | | | | |
Collapse
|
19
|
Hosomi A, Tanabe K, Hirayama H, Kim I, Rao H, Suzuki T. Identification of an Htm1 (EDEM)-dependent, Mns1-independent Endoplasmic Reticulum-associated Degradation (ERAD) pathway in Saccharomyces cerevisiae: application of a novel assay for glycoprotein ERAD. J Biol Chem 2010; 285:24324-34. [PMID: 20511219 DOI: 10.1074/jbc.m109.095919] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endoplasmic reticulum (ER)-associated degradation (ERAD) is a quality control system for newly synthesized proteins in the ER; nonfunctional proteins, which fail to form their correct folding state, are then degraded. The cytoplasmic peptide:N-glycanase is a deglycosylating enzyme that is involved in the ERAD and releases N-glycans from misfolded glycoproteins/glycopeptides. We have previously identified a mutant plant toxin protein, RTA (ricin A-chain nontoxic mutant), as the first in vivo Png1 (the cytoplasmic peptide:N-glycanase in Saccharomyces cerevisiae)-dependent ERAD substrate. Here, we report a new genetic device to assay the Png1-dependent ERAD pathway using the new model protein designated RTL (RTA-transmembrane-Leu2). Our extensive studies using different yeast mutants identified various factors involved in RTL degradation. The degradation of RTA/RTL was independent of functional Sec61 but was dependent on Der1. Interestingly, ER-mannosidase Mns1 was not involved in RTA degradation, but it was dependent on Htm1 (ERAD-related alpha-mannosidase in yeast) and Yos9 (a putative degradation lectin), indicating that mannose trimming by Mns1 is not essential for efficient ERAD of RTA/RTL. The newly established RTL assay will allow us to gain further insight into the mechanisms involved in the Png1-dependent ERAD-L pathway.
Collapse
Affiliation(s)
- Akira Hosomi
- Glycometabolome Team, RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan
| | | | | | | | | | | |
Collapse
|
20
|
Funakoshi Y, Negishi Y, Gergen JP, Seino J, Ishii K, Lennarz WJ, Matsuo I, Ito Y, Taniguchi N, Suzuki T. Evidence for an essential deglycosylation-independent activity of PNGase in Drosophila melanogaster. PLoS One 2010; 5:e10545. [PMID: 20479940 PMCID: PMC2866665 DOI: 10.1371/journal.pone.0010545] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2009] [Accepted: 04/12/2010] [Indexed: 12/03/2022] Open
Abstract
Background Peptide:N-glycanase (PNGase) is an enzyme which releases N-linked glycans from glycopeptides/glycoproteins. This enzyme plays a role in the ER-associated degradation (ERAD) pathway in yeast and mice, but the biological importance of this activity remains unknown. Principal Findings In this study, we characterized the ortholog of cytoplasmic PNGases, PNGase-like (Pngl), in Drosophila melanogaster. Pngl was found to have a molecular weight of ∼74K and was mainly localized in the cytosol. Pngl lacks a CXXC motif that is critical for enzymatic activity in other species and accordingly did not appear to possess PNGase activity, though it still retains carbohydrate-binding activity. We generated microdeletions in the Pngl locus in order to investigate the functional importance of this protein in vivo. Elimination of Pngl led to a serious developmental delay or arrest during the larval and pupal stages, and surviving mutant adult males and females were frequently sterile. Most importantly, these phenotypes were rescued by ubiquitous expression of Pngl, clearly indicating that those phenotypic consequences were indeed due to the lack of functional Pngl. Interestingly, a putative “catalytic-inactive” mutant could not rescue the growth-delay phenotype, indicating that a biochemical activity of this protein is important for its biological function. Conclusion Pngl was shown to be inevitable for the proper developmental transition and the biochemical properties other than deglycosylation activity is important for its biological function.
Collapse
Affiliation(s)
- Yoko Funakoshi
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN Advanced Science Institute, Wako, Saitama, Japan
- * E-mail: (YF); (TS)
| | - Yuki Negishi
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN Advanced Science Institute, Wako, Saitama, Japan
| | - J. Peter Gergen
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Stony Brook University, Stony Brook, New York, United States of America
| | - Junichi Seino
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN Advanced Science Institute, Wako, Saitama, Japan
| | - Kumiko Ishii
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN Advanced Science Institute, Wako, Saitama, Japan
| | - William J. Lennarz
- Department of Biochemistry and Cell Biology and Institute for Cell and Developmental Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Ichiro Matsuo
- Department of Chemistry and Chemical Biology, Gunma University, Kiryu, Gunma, Japan
| | - Yukishige Ito
- Synthetic Cellular Chemistry Laboratory, RIKEN Advanced Science Institute, Wako, Saitama, Japan
- Glycotrilogy Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
| | - Naoyuki Taniguchi
- Department of Disease Glycomics, The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, Japan
- Disease Glycomics Team, RIKEN Advanced Science Institute, Wako, Saitama, Japan
| | - Tadashi Suzuki
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN Advanced Science Institute, Wako, Saitama, Japan
- Core Research for Evolutionary Science and Technology (CREST), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
- * E-mail: (YF); (TS)
| |
Collapse
|
21
|
Hirayama H, Seino J, Kitajima T, Jigami Y, Suzuki T. Free oligosaccharides to monitor glycoprotein endoplasmic reticulum-associated degradation in Saccharomyces cerevisiae. J Biol Chem 2010; 285:12390-404. [PMID: 20150426 DOI: 10.1074/jbc.m109.082081] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In eukaryotic cells, N-glycosylation has been recognized as one of the most common and functionally important co- or post-translational modifications of proteins. "Free" forms of N-glycans accumulate in the cytosol of mammalian cells, but the precise mechanism for their formation and degradation remains unknown. Here, we report a method for the isolation of yeast free oligosaccharides (fOSs) using endo-beta-1,6-glucanase digestion. fOSs were undetectable in cells lacking PNG1, coding the cytoplasmic peptide:N-glycanase gene, suggesting that almost all fOSs were formed from misfolded glycoproteins by Png1p. Structural studies revealed that the most abundant fOS was M8B, which is not recognized well by the endoplasmic reticulum-associated degradation (ERAD)-related lectin, Yos9p. In addition, we provide evidence that some of the ERAD substrates reached the Golgi apparatus prior to retrotranslocation to the cytosol. N-Glycan structures on misfolded glycoproteins in cells lacking the cytosol/vacuole alpha-mannosidase, Ams1p, was still quite diverse, indicating that processing of N-glycans on misfolded glycoproteins was more complex than currently envisaged. Under ER stress, an increase in fOSs was observed, whereas levels of M7C, a key glycan structure recognized by Yos9p, were unchanged. Our method can thus provide valuable information on the molecular mechanism of glycoprotein ERAD in Saccharomyces cerevisiae.
Collapse
Affiliation(s)
- Hiroto Hirayama
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan
| | | | | | | | | |
Collapse
|
22
|
Maerz S, Funakoshi Y, Negishi Y, Suzuki T, Seiler S. The Neurospora peptide:N-glycanase ortholog PNG1 is essential for cell polarity despite its lack of enzymatic activity. J Biol Chem 2009; 285:2326-32. [PMID: 19940117 DOI: 10.1074/jbc.m109.045302] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Secretory proteins are subjected to a stringent endoplasmic reticulum-based quality control system that distinguishes aberrant from correctly folded proteins. The cytoplasmic peptide:N-glycanase cleaves oligosaccharides from misfolded glycoproteins and prepares them for degradation by the 26 S proteasome. In contrast to abundant in vitro data on its enzymatic function, the in vivo relevance of peptide:N-glycanase activity remains unclear. Here we show that the PNG1 ortholog from the filamentous ascomycete Neurospora crassa is an essential protein, and its deletion results in strong polarity defects. PNG1 and its predicted binding partner RAD23 have distinct functions in N. crassa and are involved in cell wall integrity and DNA repair, respectively. Moreover, wild type PNG1 has substitutions in essential catalytic amino acids, and its deglycosylation activity is lost. These substitutions are conserved in many PNG1 orthologs of the fungal kingdom, implying a so far unrecognized enzyme-independent function of PNG1 that may only become apparent in highly polar cells such as fungal hyphae.
Collapse
Affiliation(s)
- Sabine Maerz
- DFG Research Center of Molecular Physiology of the Brain (CMPB), D-37073 Goettingen, Germany
| | | | | | | | | |
Collapse
|
23
|
Funakoshi Y, Suzuki T. Glycobiology in the cytosol: the bitter side of a sweet world. Biochim Biophys Acta Gen Subj 2008; 1790:81-94. [PMID: 18952151 DOI: 10.1016/j.bbagen.2008.09.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Revised: 08/03/2008] [Accepted: 09/11/2008] [Indexed: 01/11/2023]
Abstract
Progress in glycobiology has undergone explosive growth over the past decade with more of the researchers now realizing the importance of glycan chains in various inter- and intracellular processes. However, there is still an area of glycobiology awaiting exploration. This is especially the case for the field of "glycobiology in the cytosol" which remains rather poorly understood. Yet evidence is accumulating to demonstrate that the glycoconjugates and their recognition molecules (i.e. lectins) are often present in this subcellular compartment.
Collapse
Affiliation(s)
- Yoko Funakoshi
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako Saitama, 351-0198, Japan
| | | |
Collapse
|
24
|
Molecular identification and characterization of peptide: N-glycanase from Schizosaccharomyces pombe. Biochem Biophys Res Commun 2008; 368:907-12. [PMID: 18279662 DOI: 10.1016/j.bbrc.2008.02.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 02/02/2008] [Indexed: 11/23/2022]
Abstract
Peptide:N-glycanase (PNGase) is an enzyme responsible for deglycosylation of misfolded glycoproteins in so-called endoplasmic reticulum-associated degradation (ERAD) system. In this study, we reported the molecular identification and characterization of SpPNGase (Schizosaccharomyces pombe PNGase). Enzymatic analysis revealed that SpPNGase deglycosylated the misfolded glycoproteins and distinguished native and denatured high-mannose glycoproteins in vitro. The deglycosylation activity was lost with the addition of chelating agent EDTA and was not restored by re-addition of metal ions. By construction of deletion mutant, we confirmed that N-terminal alpha-helix of SpPNGase was responsible for the protein-protein interaction. Combining the results from ternary structure prediction and dendrogram analysis, we suggested that the N-terminal alpha-helices of PNGase are derived from evolutionary motif/peptide fusion.
Collapse
|
25
|
Suzuki T, Tanabe K, Hara I, Taniguchi N, Colavita A. Dual enzymatic properties of the cytoplasmic peptide:N-glycanase in C. elegans. Biochem Biophys Res Commun 2007; 358:837-41. [PMID: 17509531 DOI: 10.1016/j.bbrc.2007.04.199] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 04/30/2007] [Indexed: 10/23/2022]
Abstract
The endoplasmic reticulum-associated degradation (ERAD) of misfolded (glyco)proteins ensures that only functional, correctly folded proteins exit from the ER and that misfolded ones are degraded by the ubiquitin-proteasome system. During the degradation of misfolded glycoproteins, some of them are subjected to deglycosylation by the cytoplasmic peptide:N-glycanase (PNGase). The cytosolic PNGase is widely distributed throughout eukaryotes. Here we show that the nematode Caenorhabditis elegans PNG-1, the cytoplasmic PNGase orthologue in this organism, exhibits dual enzyme functions, not only as PNGase but also as an oxidoreductase (thioredoxin). Using an in vitro assay as well as an in vivo assay system in budding yeast, the N-terminal thioredoxin domain and the central transglutaminase domain were found to be essential for oxidoreductase activity and PNGase activity, respectively. Occurrence of a C. elegans mutation affecting a catalytic residue in the PNGase domain strongly suggests the functional importance of this protein in higher eukaryotes.
Collapse
Affiliation(s)
- Tadashi Suzuki
- Department of Biochemistry, Osaka University Graduate School of Medicine, Japan.
| | | | | | | | | |
Collapse
|