Structural and Functional Characterization of N-Glycanase-1 Pathogenic Variants

NGLY1 deficiency is a congenital disorder of deglycosylation, caused by pathogenic variants of the <i>NGLY1</i> gene. It manifests as global developmental delay, hypo- or alacrima, hypotonia, and a primarily hyperkinetic movement disorder. The NGLY1 enzyme is involved in deglycosylation...

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Main Authors: Antje Banning, Lukas Hoeren, Isis Atallah, Ralph Orczyk, David Jacquier, Diana Ballhausen, Ritva Tikkanen
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Cells
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Online Access:https://www.mdpi.com/2073-4409/14/13/1036
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author Antje Banning
Lukas Hoeren
Isis Atallah
Ralph Orczyk
David Jacquier
Diana Ballhausen
Ritva Tikkanen
author_facet Antje Banning
Lukas Hoeren
Isis Atallah
Ralph Orczyk
David Jacquier
Diana Ballhausen
Ritva Tikkanen
author_sort Antje Banning
collection DOAJ
description NGLY1 deficiency is a congenital disorder of deglycosylation, caused by pathogenic variants of the <i>NGLY1</i> gene. It manifests as global developmental delay, hypo- or alacrima, hypotonia, and a primarily hyperkinetic movement disorder. The NGLY1 enzyme is involved in deglycosylation of misfolded N-glycosylated proteins before their proteasomal degradation and in the activation of transcription factors that control the expression of proteasomal subunits. Here, we have characterized the pathogenic NGLY1 variants found in three Swiss NGLY deficiency patients, as well as the most common pathogenic NGLY1 variant, Arg401*, found in about 20% of patients. Our functional and structural assessments of these variants show that they cause a profound reduction in NGLY1 activity, severely reduced expression of NGLY1 protein, and misprocessing of the transcription factor NFE2L1. Furthermore, transcription of proteasomal subunits and NGLY1 mRNA splicing are impaired by some of these variants. Our in silico structural analysis shows that the Arg390Gln substitution results in destabilization of NGLY1 structure due to a loss of an ionic interaction network of Arg390 and potentially impairment of protein–protein interactions. Our results provide important information on the functional and structural effects of pathogenic NGLY1 variants and pave the way for structure-based development of personalized treatment options.
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spelling doaj-art-85f3d9ee5e044c1d933f33c797aa84052025-08-20T03:50:17ZengMDPI AGCells2073-44092025-07-011413103610.3390/cells14131036Structural and Functional Characterization of N-Glycanase-1 Pathogenic VariantsAntje Banning0Lukas Hoeren1Isis Atallah2Ralph Orczyk3David Jacquier4Diana Ballhausen5Ritva Tikkanen6Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, DE-35390 Giessen, GermanyInstitute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, DE-35390 Giessen, GermanyDivision of Genetic Medicine, Lausanne University Hospital and University of Lausanne, 1005 Lausanne, SwitzerlandInstitute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, DE-35390 Giessen, GermanyPediatric Neurology and Neuro-Rehabilitation Unit, Woman-Mother-Child Department, Lausanne University Hospital and University of Lausanne, 1005 Lausanne, SwitzerlandPediatric Metabolic Unit, Pediatrics, Woman-Mother-Child Department, Lausanne University Hospital and University of Lausanne, 1005 Lausanne, SwitzerlandInstitute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, DE-35390 Giessen, GermanyNGLY1 deficiency is a congenital disorder of deglycosylation, caused by pathogenic variants of the <i>NGLY1</i> gene. It manifests as global developmental delay, hypo- or alacrima, hypotonia, and a primarily hyperkinetic movement disorder. The NGLY1 enzyme is involved in deglycosylation of misfolded N-glycosylated proteins before their proteasomal degradation and in the activation of transcription factors that control the expression of proteasomal subunits. Here, we have characterized the pathogenic NGLY1 variants found in three Swiss NGLY deficiency patients, as well as the most common pathogenic NGLY1 variant, Arg401*, found in about 20% of patients. Our functional and structural assessments of these variants show that they cause a profound reduction in NGLY1 activity, severely reduced expression of NGLY1 protein, and misprocessing of the transcription factor NFE2L1. Furthermore, transcription of proteasomal subunits and NGLY1 mRNA splicing are impaired by some of these variants. Our in silico structural analysis shows that the Arg390Gln substitution results in destabilization of NGLY1 structure due to a loss of an ionic interaction network of Arg390 and potentially impairment of protein–protein interactions. Our results provide important information on the functional and structural effects of pathogenic NGLY1 variants and pave the way for structure-based development of personalized treatment options.https://www.mdpi.com/2073-4409/14/13/1036congenital disorders of deglycosylationN-Glycosylationdevelopmental delayERADprotein misfoldingproteasome
spellingShingle Antje Banning
Lukas Hoeren
Isis Atallah
Ralph Orczyk
David Jacquier
Diana Ballhausen
Ritva Tikkanen
Structural and Functional Characterization of N-Glycanase-1 Pathogenic Variants
Cells
congenital disorders of deglycosylation
N-Glycosylation
developmental delay
ERAD
protein misfolding
proteasome
title Structural and Functional Characterization of N-Glycanase-1 Pathogenic Variants
title_full Structural and Functional Characterization of N-Glycanase-1 Pathogenic Variants
title_fullStr Structural and Functional Characterization of N-Glycanase-1 Pathogenic Variants
title_full_unstemmed Structural and Functional Characterization of N-Glycanase-1 Pathogenic Variants
title_short Structural and Functional Characterization of N-Glycanase-1 Pathogenic Variants
title_sort structural and functional characterization of n glycanase 1 pathogenic variants
topic congenital disorders of deglycosylation
N-Glycosylation
developmental delay
ERAD
protein misfolding
proteasome
url https://www.mdpi.com/2073-4409/14/13/1036
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AT lukashoeren structuralandfunctionalcharacterizationofnglycanase1pathogenicvariants
AT isisatallah structuralandfunctionalcharacterizationofnglycanase1pathogenicvariants
AT ralphorczyk structuralandfunctionalcharacterizationofnglycanase1pathogenicvariants
AT davidjacquier structuralandfunctionalcharacterizationofnglycanase1pathogenicvariants
AT dianaballhausen structuralandfunctionalcharacterizationofnglycanase1pathogenicvariants
AT ritvatikkanen structuralandfunctionalcharacterizationofnglycanase1pathogenicvariants