PUBLICATION
Mutation in human CLPX elevates levels of δ-aminolevulinate synthase and protoporphyrin IX to promote erythropoietic protoporphyria.
- Authors
- Yien, Y.Y., Ducamp, S., van der Vorm, L.N., Kardon, J.R., Manceau, H., Kannengiesser, C., Bergonia, H.A., Kafina, M.D., Karim, Z., Gouya, L., Baker, T.A., Puy, H., Phillips, J.D., Nicolas, G., Paw, B.H.
- ID
- ZDB-PUB-170926-15
- Date
- 2017
- Source
- Proceedings of the National Academy of Sciences of the United States of America 114(38): E8045–E8052 (Journal)
- Registered Authors
- Paw, Barry
- Keywords
- AAA+ ATPase, ALAS, heme biosynthesis, porphyria, protein unfoldases
- MeSH Terms
-
- 5-Aminolevulinate Synthetase/genetics
- 5-Aminolevulinate Synthetase/metabolism*
- Adolescent
- Amino Acid Substitution
- Endopeptidase Clp*/genetics
- Endopeptidase Clp*/metabolism
- Enzyme Stability/genetics
- Female
- Humans
- Male
- Mutation, Missense*
- Porphyria, Erythropoietic*/genetics
- Porphyria, Erythropoietic*/metabolism
- Porphyria, Erythropoietic*/pathology
- Protoporphyrins/biosynthesis*
- Protoporphyrins/genetics
- PubMed
- 28874591 Full text @ Proc. Natl. Acad. Sci. USA
Citation
Yien, Y.Y., Ducamp, S., van der Vorm, L.N., Kardon, J.R., Manceau, H., Kannengiesser, C., Bergonia, H.A., Kafina, M.D., Karim, Z., Gouya, L., Baker, T.A., Puy, H., Phillips, J.D., Nicolas, G., Paw, B.H. (2017) Mutation in human CLPX elevates levels of δ-aminolevulinate synthase and protoporphyrin IX to promote erythropoietic protoporphyria.. Proceedings of the National Academy of Sciences of the United States of America. 114(38):E8045–E8052.
Abstract
Loss-of-function mutations in genes for heme biosynthetic enzymes can give rise to congenital porphyrias, eight forms of which have been described. The genetic penetrance of the porphyrias is clinically variable, underscoring the role of additional causative, contributing, and modifier genes. We previously discovered that the mitochondrial AAA+ unfoldase ClpX promotes heme biosynthesis by activation of δ-aminolevulinate synthase (ALAS), which catalyzes the first step of heme synthesis. CLPX has also been reported to mediate heme-induced turnover of ALAS. Here we report a dominant mutation in the ATPase active site of human CLPX, p.Gly298Asp, that results in pathological accumulation of the heme biosynthesis intermediate protoporphyrin IX (PPIX). Amassing of PPIX in erythroid cells promotes erythropoietic protoporphyria (EPP) in the affected family. The mutation in CLPX inactivates its ATPase activity, resulting in coassembly of mutant and WT protomers to form an enzyme with reduced activity. The presence of low-activity CLPX increases the posttranslational stability of ALAS, causing increased ALAS protein and ALA levels, leading to abnormal accumulation of PPIX. Our results thus identify an additional molecular mechanism underlying the development of EPP and further our understanding of the multiple mechanisms by which CLPX controls heme metabolism.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping