Journal
HUMAN MUTATION
Volume 36, Issue 9, Pages 851-860Publisher
WILEY
DOI: 10.1002/humu.22817
Keywords
phosphomannomutase 2; PMM2; congenital disorders of glycosylation; PMM2-CDG; protein stability
Categories
Funding
- Fundacion Ramon Areces grant
- MINECO [IPT-2012-0561-010000, PI11/01250]
- Ramon y Cajal grant from the Ministerio de Ciencia y Tecnologia
Ask authors/readers for more resources
Congenital disorder of glycosylation type Ia (PMM2-CDG), the most common form of CDG, is caused by mutations in the PMM2 gene that reduce phosphomannomutase 2 (PMM2) activity. No curative treatment is available. The present work describes the functional analysis of nine human PMM2 mutant proteins frequently found in PMM2-CDG patients and also two murine Pmm2 mutations carried by the unique PMM2-CDG mouse model described to overcome embryonic lethality. The effects of the mutations on PMM2/Pmm2 stability, oligomerization, and enzyme activity were explored in an optimized bacterial system. The mutant proteins were associated with an enzymatic activity of up to 47.3% as compared with wild type (WT). Stability analysis performed using differential scanning fluorimetry and a bacterial transcription-translation-coupled system allowed the identification of several destabilizing mutations (p.V44A, p.D65Y, p.R123Q, p.R141H, p.R162W, p.F207S, p.T237M, p.C241S). Exclusion chromatography identified one mutation, p.P113L, that affected dimer interaction. Expression analysis of the p.V44A, p.D65Y, p.R162W, and p.T237M mutations in a eukaryotic expression system under permissive folding conditions showed the possibility of recovering their associated PMM2 activity. Together, the results suggest that some loss-of-function mutations detected in PMM2-CDG patients could be destabilizing, and therefore PMM2 activity could be, in certain cases, rescuable via the use of synergetic proteostasis modulators and/or chaperones. (C) 2015 Wiley Periodicals, Inc.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available