Journal article
Mitochondrial glutamic-oxaloacetic transaminase (GOT2) in the growth of C2C12 myoblasts
Journal of bioenergetics and biomembranes, Vol.57(2-3), pp.85-95
06/2025
DOI: 10.1007/s10863-025-10053-2
PMID: 39954225
Abstract
Glutamine is well recognized as critical to the growth of most cell types. Within mitochondria glutamine is converted to glutamate by glutaminase. Oxaloacetate and glutamate then react to form alpha-ketoglutarate (α-KG) and aspartate catalyzed by glutamic-oxaloacetic transaminase (GOT2) or directly converted to α-KG by glutamate dehydrogenase (GDH). We investigated the role of GOT2 in mediating glutamate metabolism and cell growth in undifferentiated C2C12 cells. CRISPR mediated GOT2 knockout (KO) impaired cell growth, partially overcome by higher concentrations of glutamine. Mitochondrial respiration did not differ between KO and wildtype (WT) cells. Metabolite profiling showed that GOT2KO decreased aspartate by about 50% in KO versus WT cells. In contrast, α-KG increased. Metabolites reflecting the pentose phosphate pathway were significantly increased in KO cells. Metabolic pathway analyses revealed alteration of the TCA cycle, the pentose phosphate pathway, and amino acid metabolism. Glutamine 13C-tracing revealed decreased generation of aspartate, increased ribulose phosphate and evidence for reductive carboxylation of α-KG to isocitrate in KO cells. GDH expression was detected in C2C12 cells but did not differ between WT and GOT2KO mitochondria. GDH is not or barely expressed in adult muscle, however, we observed clear expression in pre-weanling mice. Cytosolic glutamic-oxaloacetic transaminase, GOT1, expression did not differ between GOT2KO and WT cells. In summary, GOT2 is necessary for glutamate flux and generation of downstream metabolites needed for the growth of C2C12 myoblasts. Although respiration did not differ, lack of aspartate and other compounds needed for cell proliferation may have been major factors impairing growth.Glutamine is well recognized as critical to the growth of most cell types. Within mitochondria glutamine is converted to glutamate by glutaminase. Oxaloacetate and glutamate then react to form alpha-ketoglutarate (α-KG) and aspartate catalyzed by glutamic-oxaloacetic transaminase (GOT2) or directly converted to α-KG by glutamate dehydrogenase (GDH). We investigated the role of GOT2 in mediating glutamate metabolism and cell growth in undifferentiated C2C12 cells. CRISPR mediated GOT2 knockout (KO) impaired cell growth, partially overcome by higher concentrations of glutamine. Mitochondrial respiration did not differ between KO and wildtype (WT) cells. Metabolite profiling showed that GOT2KO decreased aspartate by about 50% in KO versus WT cells. In contrast, α-KG increased. Metabolites reflecting the pentose phosphate pathway were significantly increased in KO cells. Metabolic pathway analyses revealed alteration of the TCA cycle, the pentose phosphate pathway, and amino acid metabolism. Glutamine 13C-tracing revealed decreased generation of aspartate, increased ribulose phosphate and evidence for reductive carboxylation of α-KG to isocitrate in KO cells. GDH expression was detected in C2C12 cells but did not differ between WT and GOT2KO mitochondria. GDH is not or barely expressed in adult muscle, however, we observed clear expression in pre-weanling mice. Cytosolic glutamic-oxaloacetic transaminase, GOT1, expression did not differ between GOT2KO and WT cells. In summary, GOT2 is necessary for glutamate flux and generation of downstream metabolites needed for the growth of C2C12 myoblasts. Although respiration did not differ, lack of aspartate and other compounds needed for cell proliferation may have been major factors impairing growth.
Details
- Title: Subtitle
- Mitochondrial glutamic-oxaloacetic transaminase (GOT2) in the growth of C2C12 myoblasts
- Creators
- Ritu Som - University of IowaBrian D Fink - University of IowaAdam J Rauckhorst - University of IowaEric B Taylor - University of IowaWilliam I Sivitz - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of bioenergetics and biomembranes, Vol.57(2-3), pp.85-95
- DOI
- 10.1007/s10863-025-10053-2
- PMID
- 39954225
- NLM abbreviation
- J Bioenerg Biomembr
- ISSN
- 1573-6881
- eISSN
- 1573-6881
- Publisher
- SPRINGER/PLENUM PUBLISHERS
- Grant note
- American Heart AssociationUniversity of Iowa Carver College of Medicine Metabolomics Core Facility
The authors thank the University of Iowa Carver College of Medicine Metabolomics Core Facility
- Language
- English
- Electronic publication date
- 02/15/2025
- Date published
- 06/2025
- Academic Unit
- Molecular Physiology and Biophysics; Pathology; Fraternal Order of Eagles Diabetes Research Center; Neuroscience and Pharmacology; Endocrinology and Metabolism; Internal Medicine
- Record Identifier
- 9984787234602771
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