A Truncated Mutant – The Most Common Sucrase‐Isomaltase Deficiency in the Inuit Population: Cellular and Biochemical Characterization
Sucrase isomaltase (SI) is the most prominent disaccharidase in the small intestine responsible for the final steps of carbohydrate digestion. Mutations in the SI gene can lead to a drastic reduction or loss of the catalytic activity required for digestion of disaccharides, and thus can be associate...
Published in: | The FASEB Journal |
---|---|
Main Authors: | , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2022
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1096/fasebj.2022.36.s1.r3339 |
id |
crwiley:10.1096/fasebj.2022.36.s1.r3339 |
---|---|
record_format |
openpolar |
spelling |
crwiley:10.1096/fasebj.2022.36.s1.r3339 2024-06-02T08:09:33+00:00 A Truncated Mutant – The Most Common Sucrase‐Isomaltase Deficiency in the Inuit Population: Cellular and Biochemical Characterization Tannous, Stephanie Naim, Hassan Y. Deutsche Forschungsgemeinschaft 2022 http://dx.doi.org/10.1096/fasebj.2022.36.s1.r3339 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor The FASEB Journal volume 36, issue S1 ISSN 0892-6638 1530-6860 journal-article 2022 crwiley https://doi.org/10.1096/fasebj.2022.36.s1.r3339 2024-05-03T11:25:40Z Sucrase isomaltase (SI) is the most prominent disaccharidase in the small intestine responsible for the final steps of carbohydrate digestion. Mutations in the SI gene can lead to a drastic reduction or loss of the catalytic activity required for digestion of disaccharides, and thus can be associated with maldigestion and malabsorption of carbohydrates. Carbohydrate malabsorption is one of the most common gastrointestinal problems, where 70% of the population are affected. Congenital sucrase‐isomaltase deficiency (CSID) is an autosomal recessive disorder caused by defective SI activity; and it is clinically characterized by abdominal pain, flatulence, bloating, and diarrhea. Recently, a homozygous frameshift mutation, c.273_274delAG (p.Gly92Leufs*8), was identified in the Inuit population with an observed allele frequency of 17.2%. In this study, Cos‐1 cells were transiently transfected with cDNA encoding the Gly92Leufs*8 mutation or SI wild‐type (SI‐WT) as a control. The assessment of this new variant phenotype was investigated through enzymatic activity measurements, cellular localization and trafficking behavior. The truncation is associated with the elimination of all N‐glycosylation sites, whereas the Ser/Thr‐rich stalk region is retained pointing to a potential O‐glycosylation. In fact, treatment with benzyl 2‐acetamido‐2‐deoxy‐α‐D‐galactopyranoside, an inhibitor of O‐glycosylation in the Golgi, resulted in a substantial shift in the size of the mutant concomitant with transport competence of the mutant to O‐glycosylation in the Golgi Apparatus. The mutant is further trafficked to the cell surface as assessed by the detection of biotinylated forms of the mutant at the cell surface. This result was also corroborated by immunofluorescence images, which revealed the mutant at the cell surface. However, this mutant does not exhibit SI activity due to the absence of the sucrase and isomaltase domains. While our data unraveled the molecular basis for the onset of the clinical symptoms in patients homozygous to ... Article in Journal/Newspaper inuit Wiley Online Library The FASEB Journal 36 S1 |
institution |
Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
Sucrase isomaltase (SI) is the most prominent disaccharidase in the small intestine responsible for the final steps of carbohydrate digestion. Mutations in the SI gene can lead to a drastic reduction or loss of the catalytic activity required for digestion of disaccharides, and thus can be associated with maldigestion and malabsorption of carbohydrates. Carbohydrate malabsorption is one of the most common gastrointestinal problems, where 70% of the population are affected. Congenital sucrase‐isomaltase deficiency (CSID) is an autosomal recessive disorder caused by defective SI activity; and it is clinically characterized by abdominal pain, flatulence, bloating, and diarrhea. Recently, a homozygous frameshift mutation, c.273_274delAG (p.Gly92Leufs*8), was identified in the Inuit population with an observed allele frequency of 17.2%. In this study, Cos‐1 cells were transiently transfected with cDNA encoding the Gly92Leufs*8 mutation or SI wild‐type (SI‐WT) as a control. The assessment of this new variant phenotype was investigated through enzymatic activity measurements, cellular localization and trafficking behavior. The truncation is associated with the elimination of all N‐glycosylation sites, whereas the Ser/Thr‐rich stalk region is retained pointing to a potential O‐glycosylation. In fact, treatment with benzyl 2‐acetamido‐2‐deoxy‐α‐D‐galactopyranoside, an inhibitor of O‐glycosylation in the Golgi, resulted in a substantial shift in the size of the mutant concomitant with transport competence of the mutant to O‐glycosylation in the Golgi Apparatus. The mutant is further trafficked to the cell surface as assessed by the detection of biotinylated forms of the mutant at the cell surface. This result was also corroborated by immunofluorescence images, which revealed the mutant at the cell surface. However, this mutant does not exhibit SI activity due to the absence of the sucrase and isomaltase domains. While our data unraveled the molecular basis for the onset of the clinical symptoms in patients homozygous to ... |
author2 |
Deutsche Forschungsgemeinschaft |
format |
Article in Journal/Newspaper |
author |
Tannous, Stephanie Naim, Hassan Y. |
spellingShingle |
Tannous, Stephanie Naim, Hassan Y. A Truncated Mutant – The Most Common Sucrase‐Isomaltase Deficiency in the Inuit Population: Cellular and Biochemical Characterization |
author_facet |
Tannous, Stephanie Naim, Hassan Y. |
author_sort |
Tannous, Stephanie |
title |
A Truncated Mutant – The Most Common Sucrase‐Isomaltase Deficiency in the Inuit Population: Cellular and Biochemical Characterization |
title_short |
A Truncated Mutant – The Most Common Sucrase‐Isomaltase Deficiency in the Inuit Population: Cellular and Biochemical Characterization |
title_full |
A Truncated Mutant – The Most Common Sucrase‐Isomaltase Deficiency in the Inuit Population: Cellular and Biochemical Characterization |
title_fullStr |
A Truncated Mutant – The Most Common Sucrase‐Isomaltase Deficiency in the Inuit Population: Cellular and Biochemical Characterization |
title_full_unstemmed |
A Truncated Mutant – The Most Common Sucrase‐Isomaltase Deficiency in the Inuit Population: Cellular and Biochemical Characterization |
title_sort |
truncated mutant – the most common sucrase‐isomaltase deficiency in the inuit population: cellular and biochemical characterization |
publisher |
Wiley |
publishDate |
2022 |
url |
http://dx.doi.org/10.1096/fasebj.2022.36.s1.r3339 |
genre |
inuit |
genre_facet |
inuit |
op_source |
The FASEB Journal volume 36, issue S1 ISSN 0892-6638 1530-6860 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1096/fasebj.2022.36.s1.r3339 |
container_title |
The FASEB Journal |
container_volume |
36 |
container_issue |
S1 |
_version_ |
1800755284817215488 |