Functional Characterization of <i>FH</i> Mutation c.557G>A Underlies Uterine Leiomyomas
The <i>FH</i> gene encodes the fumarate hydratase of the Krebs cycle and functions as a homotetramer to catalyze the hydration of fumarate to malate. Mutations in <i>FH</i> result in uterine leiomyomas, a rare autosomal dominant inherited metabolic disease. However, how <i...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-01-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/3/1452 |
| Summary: | The <i>FH</i> gene encodes the fumarate hydratase of the Krebs cycle and functions as a homotetramer to catalyze the hydration of fumarate to malate. Mutations in <i>FH</i> result in uterine leiomyomas, a rare autosomal dominant inherited metabolic disease. However, how <i>FH</i> mutations result in this disease is poorly understood. Here, the <i>FH</i> mutation c.557G>A (p.S186N) was identified in a family with uterine leiomyomas phenotype. A series of studies were performed to confirm the pathogenicity of this mutation. Results showed that the FH mutant exhibited significantly lower fumarase enzyme activity and increased the fumarates level compared with the wildtype, which might be due to the impaired homotetramer formation in the native gel electrophoresis. Interestingly, the immunofluorescence study revealed that the overexpressed FH mutant exhibited puncta structures compared with the evenly expressed FH wildtype in cytoplasm suggesting that the altered amino acid might result in dysfunctional proteins which were accumulated to reduce its cytotoxicity. Importantly, the cells overexpressing the FH mutant exhibited higher proliferation and extracellular acidification rate value (ECAR) which might be caused by the upregulated HIF-1<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">α</mi></semantics></math></inline-formula> indicating the tumor phenotype. Notably, phospho-mTOR was significantly increased and autophagy was inhibited in the FH mutant overexpression cells compared with the wildtype. Our work provides new insight into the <i>FH</i> mutation c.557G>A (p.S186N) underlies uterine leiomyomas and important information for accurate genetic counseling and clinical diagnosis of the disease. |
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| ISSN: | 1661-6596 1422-0067 |