Human RFT1 Deficiency Leads to a Disorder of N-Linked Glycosylation
N-linked glycosylation is an essential posttranslational modification of proteins in eukaryotes. The substrate of N-linked glycosylation, dolichol pyrophosphate (DolPP)-GlcNAc 2Man 9Glc 3, is assembled through a complex series of ordered reactions requiring the translocation of the intermediate DolP...
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Published in | American journal of human genetics Vol. 82; no. 3; pp. 600 - 606 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Chicago, IL
Elsevier Inc
01.03.2008
University of Chicago Press Cell Press American Society of Human Genetics |
Subjects | |
Online Access | Get full text |
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Summary: | N-linked glycosylation is an essential posttranslational modification of proteins in eukaryotes. The substrate of N-linked glycosylation, dolichol pyrophosphate (DolPP)-GlcNAc
2Man
9Glc
3, is assembled through a complex series of ordered reactions requiring the translocation of the intermediate DolPP-GlcNAc
2Man
5 structure across the endoplasmic-reticulum membrane. A young patient diagnosed with a congenital disorder of glycosylation characterized by an intracellular accumulation of DolPP-GlcNAc
2Man
5 was found to carry a homozygous point mutation in the
RFT1 gene. The c.199C→T mutation introduced the amino acid substitution p.R67C. The human RFT1 protein shares 22% identity with its yeast ortholog, which is involved in the translocation of DolPP-GlcNAc
2Man
5 from the cytosolic into the lumenal side of the endoplasmic reticulum. Despite the low sequence similarity between the yeast and the human RFT1 proteins, we demonstrated both their functional orthology and the pathologic effect of the human p.R67C mutation by complementation assay in
Δrft1 yeast cells. The causality of the RFT1 p.R67C mutation was further established by restoration of normal glycosylation profiles in patient-derived fibroblasts after lentiviral expression of a normal
RFT1 cDNA. The definition of the RFT1 defect establishes the functional conservation of the DolPP-GlcNAc
2Man
5 translocation process in eukaryotes. RFT1 deficiency in both yeast and human cells leads to the accumulation of incomplete DolPP-GlcNAc
2Man
5 and to a profound glycosylation disorder in humans. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 These authors contributed equally to this work. |
ISSN: | 0002-9297 1537-6605 |
DOI: | 10.1016/j.ajhg.2007.12.021 |