Two human patient mitochondrial pyruvate carrier mutations reveal distinct molecular mechanisms of dysfunction.
JCI Insight
; 52019 05 30.
Article
en En
| MEDLINE
| ID: mdl-31145700
ABSTRACT
The Mitochondrial Pyruvate Carrier (MPC) occupies a central metabolic node by transporting cytosolic pyruvate into the mitochondrial matrix and linking glycolysis with mitochondrial metabolism. Two reported human MPC1 mutations cause developmental abnormalities, neurological problems, metabolic deficits, and for one patient, early death. We aimed to understand biochemical mechanisms by which the human patient C289T and T236A MPC1 alleles disrupt MPC function. MPC1 C289T encodes two protein variants, a mis-spliced, truncation mutant (A58G) and a full length point mutant (R97W). MPC1 T236A encodes a full length point mutant (L79H). Using human patient fibroblasts and complementation of CRISPR-deleted, MPC1 null mouse C2C12 cells, we investigated how MPC1 mutations cause MPC deficiency. Truncated MPC1 A58G protein was intrinsically unstable and failed to form MPC complexes. The MPC1 R97W protein was less stable but when overexpressed formed complexes with MPC2 that retained pyruvate transport activity. Conversely, MPC1 L79H protein formed stable complexes with MPC2, but these complexes failed to transport pyruvate. These findings inform MPC structure-function relationships and delineate three distinct biochemical pathologies resulting from two human patient MPC1 mutations. They also illustrate an efficient gene pass-through system for mechanistically investigating human inborn errors in pyruvate metabolism.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Transportadores de Ácidos Monocarboxílicos
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Proteínas de Transporte de Membrana Mitocondrial
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Mitocondrias
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Mutación
Límite:
Adolescent
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Adult
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Animals
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Child
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Female
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Humans
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Male
Idioma:
En
Revista:
JCI Insight
Año:
2019
Tipo del documento:
Article
País de afiliación:
Estados Unidos