Complementation of a pathogenic IFNGR2 misfolding mutation with modifiers of N-glycosylation.
Germline mutations may cause human disease by various mechanisms. Missense and other in-frame mutations may be deleterious because the mutant proteins are not correctly targeted, do not function correctly, or both. We studied a child with mycobacterial disease caused by homozygosity for a novel in-frame microinsertion in IFNGR2. In cells transfected with the mutant allele, most of the interferon gamma receptor 2 (IFN-gamma R2) protein was retained within the cell, and that expressed on the cell surface had an abnormally high molecular weight (MW). The misfolding mutation was not gain-of-glycosylation, as it created no new N-glycosylation site. The mutant IFNGR2 allele was null, as the patient's cells did not respond to IFN-gamma. Based on the well-established relationship between protein N-glycosylation and protein quality control processes, we tested 29 compounds affecting maturation by N-glycosylation in the secretory pathway. Remarkably, up to 13 of these compounds reduced the MW of surface-expressed mutant IFN-gamma R2 molecules and restored cellular responsiveness to IFN-gamma. Modifiers of N-glycosylation may therefore complement human cells carrying in-frame and misfolding, but not necessarily gain-of-glycosylation, mutations in genes encoding proteins subject to trafficking via the secretory pathway. Some of these compounds are available for clinical use, paving the way for clinical trials of chemical complementation for various human genetic traits.
Vogt
Guillaume
G
Laboratory of Human Genetics of Infectious Diseases, U550, Institut National de la Santé et de la Recherche Médicale (INSERM), 75015 Paris, France. vogt@necker.fr
Bustamante
Jacinta
J
Chapgier
Ariane
A
Feinberg
Jacqueline
J
Boisson Dupuis
Stephanie
S
Picard
Capucine
C
Mahlaoui
Nizar
N
Gineau
Laure
L
Alcaïs
Alexandre
A
Lamaze
Christophe
C
Puck
Jennifer M
JM
de Saint Basile
Geneviève
G
Khayat
Claudia Djambas
CD
Mikhael
Raymond
R
Casanova
Jean-Laurent
JL
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D002675:Child, Preschool; D003241:Consanguinity; D004247:DNA / Q000235:genetics; D005260:Female; D005816:Genetic Complementation Test; D006031:Glycosylation; D006720:Homozygote; D006801:Humans; D008297:Male; D016254:Mutagenesis, Insertional; D009154:Mutation; D015270:Mycobacterium avium-intracellulare Infection / Q000235:genetics / Q000276:immunology; D010375:Pedigree; D010641:Phenotype; D017510:Protein Folding; D017471:Receptors, Interferon / Q000737:chemistry* / Q000172:deficiency / Q000235:genetics*; D017384:Sequence Deletion; D014162:Transfection
C086185:IFNGR2 protein, human; D017471:Receptors, Interferon; D004247:DNA