Affinage

GCSH

Glycine cleavage system H protein, mitochondrial · UniProt P23434

Length
173 aa
Mass
18.9 kDa
Annotated
2026-06-10
13 papers in source corpus 7 papers cited in narrative 8 extracted findings
Cross-family judge vs UniProt: tie faithfulness: 4/4 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

GCSH encodes the H-protein, a mitochondrial lipoyl-carrier component of the glycine cleavage system that participates in glycine decarboxylation and one-carbon metabolism while also serving as a lipoyl-transfer scaffold required for lipoylation of bioenergetic enzymes including pyruvate dehydrogenase and 2-ketoglutarate dehydrogenase (PMID:36190515). Unlike the limited tissue expression of the P-protein gene GLDC, GCSH is broadly expressed across human tissues, consistent with a role beyond glycine catabolism alone (PMID:11450847). Genetic evidence places GCSH within the glycine cleavage pathway, with biallelic pathogenic variants causing combined deficiency of both lipoylation and glycine metabolism—most variants acting as hypomorphs on both functions and certain missense variants affecting predominantly one (PMID:36190515); heterozygous GCSH variants are associated with transient neonatal hyperglycinemia (PMID:12402263). The two functions are separable in disease: reduction of GCSH protein in GLDC-deficient brain coincides with diminished PDH lipoylation and remodeling of mitochondrial energy metabolism. In metabolic and oncologic contexts, GCSH-driven glycine catabolism depletes glycine available for glutathione synthesis, lowering the GSH/GSSG ratio and sensitizing cells to copper-dependent cell death (cuproptosis); GCSH acts downstream of PI3K/AKT signaling and is linked to FDX1-mediated cuproptosis regulation (PMID:41591502, PMID:42082057).

Mechanistic history

Synthesis pass · year-by-year structured walk · 7 steps
  1. 2001 Medium

    Established the genomic structure and expression pattern of GCSH, distinguishing its regulation from other glycine cleavage system components and hinting at a broader role.

    Evidence PAC clone isolation, FISH mapping, transcription initiation mapping, and tissue dot-blot expression profiling

    PMID:11450847

    Open questions at the time
    • Does not define the functional consequence of broad tissue expression
    • No protein-level or enzymatic characterization
  2. 2002 Medium

    Placed GCSH genetically within the glycine cleavage system by linking heterozygous variants to transient glycine elevation.

    Evidence Mutation screening of GLDC, AMT, and GCSH in three transient neonatal hyperglycinemia patients

    PMID:12402263

    Open questions at the time
    • Very small cohort
    • Heterozygous-variant causality not functionally proven
  3. 2006 Medium

    Defined the relative genetic contribution of GCS components to nonketotic hyperglycinemia, with GLDC and AMT dominant and no GCSH coding mutations in the cohort.

    Evidence Complete coding-region sequencing of GLDC, AMT, and GCSH in 69 NKH families with haplotype analysis

    PMID:16450403

    Open questions at the time
    • Negative result for GCSH does not exclude rare or non-coding variants
    • No functional assays for GCSH
  4. 2018 Medium

    Identified a transcript-level regulatory axis in which a sense GCSH variant promotes glycine decarboxylation and cell viability while an antisense-like variant counteracts it.

    Evidence Overexpression of Tv1/Tv* transcripts, Tv1-Tv* RNA-binding assay, and metabolic/viability readouts in breast cancer cells

    PMID:30337557

    Open questions at the time
    • Mechanism of Tv* RNA action not defined
    • Single cancer cell context
  5. 2023 High

    Resolved GCSH as a dual-function (moonlighting) protein required for both glycine metabolism and lipoylation of bioenergetic enzymes, with variant-specific functional effects causing combined deficiency.

    Evidence Patient fibroblasts, GCSH knockdown in COS7 and yeast, molecular modeling, and in vitro protein studies

    PMID:36190515

    Open questions at the time
    • Structural basis for separating the two functions only modeled
    • Lipoyl-transfer biochemistry not fully reconstituted
  6. 2025 Medium

    Showed in vivo that GCSH decline in GLDC deficiency reduces PDH lipoylation and remodels brain mitochondrial energy metabolism, connecting the two GCSH functions in a disease model.

    Evidence Attenuated Gldc mutant mouse brain, Western blotting for GCSH/lipoylation, and metabolic profiling (preprint)

    Open questions at the time
    • Preprint, not peer-reviewed
    • Causality of GCSH loss versus secondary GLDC effects not isolated
  7. 2026 Medium

    Defined a glycine-GSH-cuproptosis axis in which GCSH-driven glycine catabolism depletes glutathione and modulates copper-dependent cell death, downstream of PI3K/AKT and linked to FDX1.

    Evidence shRNA knockdown in colorectal cancer and hepatocyte/HepG2 cells, HFHC/MASH mouse models, BSO/glycine rescue, cuproptosis markers, and molecular docking

    PMID:41591502 PMID:42082057

    Open questions at the time
    • GCSH-FDX1 interaction only computational, not biochemically validated
    • Cuproptosis-resistance role derived from cancer/MASH contexts only

Open questions

Synthesis pass · forward-looking unresolved questions
  • How the lipoyl-transfer and glycine-decarboxylation activities of GCSH are structurally partitioned and regulated, and whether GCSH directly interacts with FDX1, remain unresolved.
  • No experimentally validated GCSH-FDX1 binding
  • No reconstituted structural model separating the two functions
  • Regulation of GCSH abundance across tissues uncharacterized

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140098 catalytic activity, acting on RNA 2 GO:0140096 catalytic activity, acting on a protein 1
Localization
GO:0005739 mitochondrion 2
Pathway
R-HSA-1430728 Metabolism 2 R-HSA-5357801 Programmed Cell Death 1
Partners
FDX1
Complex memberships
glycine cleavage system

Evidence

Reading pass · 8 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2001 GCSH (H-protein gene) spans 13.5 kb, consists of five exons, and maps to chromosome 16q24. The transcription initiation site was determined and potential binding sites for transcriptional factors were found in the 5' upstream region. GCSH mRNA is expressed in all 29 human tissues examined, in contrast to P-protein (GLDC), which is expressed only in a limited number of tissues, suggesting distinct transcriptional regulation of each glycine cleavage system (GCS) constituent. PAC clone isolation, FISH chromosomal mapping, oligonucleotide-cap method (transcription initiation), dot-blot analysis of tissue expression Journal of human genetics Medium 11450847
2006 Mutations in GLDC and AMT (but not GCSH) were identified as the predominant genetic causes of nonketotic hyperglycinemia (NKH) in a comprehensive screen of 69 families; no GCSH mutations were found. GLDC mutations clustered in exon 19 (cofactor-binding site Lys754). A large GLDC exon 1 deletion of multiple independent origins was found across ethnic groups. Complete coding-region sequencing of GLDC, AMT, and GCSH in 69 NKH families; haplotype analysis Human mutation Medium 16450403
2002 Heterozygous mutations in GCSH (and GLDC) were identified in patients with transient neonatal hyperglycinemia, establishing that heterozygous carriers for NKH-associated genes can develop transient glycine elevation, placing GCSH in the glycine cleavage system pathway. Mutation screening of GLDC, AMT, and GCSH in three transient neonatal hyperglycinemia patients Annals of neurology Medium 12402263
2023 GCSH (H-protein) has a dual role: (1) participation in the glycine cleavage system (one-carbon/glycine metabolism) and (2) protein lipoylation required for bioenergetic enzymes including pyruvate dehydrogenase (PDH) and 2-ketoglutarate dehydrogenase. Biallelic pathogenic variants in GCSH cause combined deficiency of both mitochondrial activities. Functional studies in patient fibroblasts, GCSH knockdown in COS7 cells and yeast, molecular modeling, and in vitro protein studies demonstrated that most variants produce a hypomorphic effect on both lipoylation and glycine metabolism, whereas some missense variants affect primarily one function. Functional studies in patient fibroblasts, GCSH knockdown in COS7 cells and yeast, molecular modeling, in vitro protein studies, expression analysis Human molecular genetics High 36190515
2018 GCSH transcript variant 1 (Tv1, protein-coding) overexpression in breast cancer cells increased cellular vitality primarily by accelerating mitochondrial glycine decarboxylation activity. A shorter antisense-like transcript variant (Tv*) can bind Tv1 RNA; Tv1-Tv* RNA binding and overexpression of Tv* led to decreased metabolic activity, membrane damage, and necrosis, establishing a regulatory axis at the transcript level that controls glycine decarboxylation and cell viability. Overexpression studies of Tv1 and Tv* transcripts, Tv1-Tv* RNA-binding assay, metabolic activity assays (LDH release, extracellular acidification, mitochondrial glycine decarboxylation activity measurement) Scientific reports Medium 30337557
2025 In attenuated Gldc mutant mouse brains, GCSH (mitochondrial lipoyl-transfer protein) protein levels were reduced >5-fold alongside reduced lipoylation of the pyruvate dehydrogenase (PDH) complex, accompanied by activation of astrocyte mitochondrial β-oxidation and neuronal PDH activation. This establishes that GCSH decline contributes to remodeling of mitochondrial energy metabolism in the context of GLDC deficiency. Mouse model of NKH (attenuated Gldc mutation), Western blotting for GCSH and lipoylation markers, metabolic profiling of brain bioRxivpreprint Medium
2026 GCSH knockdown in colorectal cancer cells suppressed cuproptosis by downregulating FDX1 protein and reducing intracellular Cu2+ and ROS accumulation. Molecular docking suggested a potential GCSH–FDX1 interaction. GCSH was identified as a downstream effector of the PI3K/AKT pathway, and rescue experiments placed GCSH between PI3K/AKT activation and FDX1-mediated cuproptosis resistance. shRNA knockdown, flow cytometry, Western blotting, intracellular Cu2+/ROS measurement, molecular docking, rescue experiments, CCK-8/wound healing/Transwell assays Functional & integrative genomics Low 41591502
2026 In MASH (metabolic dysfunction-associated steatohepatitis) models, GCSH upregulation enhances glycine catabolism, depleting glycine as a substrate for glutathione (GSH) synthesis and thereby reducing GSH/GSSG ratios. Gcsh knockdown suppressed cuproptosis and ameliorated MASH phenotypes; rescue experiments with the GSH synthesis inhibitor BSO reversed protection from Gcsh knockdown, establishing that GSH is a downstream effector of GCSH in a glycine–GSH–cuproptosis regulatory axis. shRNA-mediated Gcsh knockdown in primary hepatocytes and HepG2 cells, in vivo HFHC diet mouse model, rescue with exogenous glycine and BSO, cuproptosis marker assessment (DLAT oligomerization, Fe-S cluster proteins), metabolic assays (GSH/GSSG, mitochondrial function) Free radical biology & medicine Medium 42082057

Source papers

Stage 0 corpus · 13 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2006 Comprehensive mutation analysis of GLDC, AMT, and GCSH in nonketotic hyperglycinemia. Human mutation 80 16450403
2001 Chromosomal localization, structure, single-nucleotide polymorphisms, and expression of the human H-protein gene of the glycine cleavage system (GCSH), a candidate gene for nonketotic hyperglycinemia. Journal of human genetics 31 11450847
2002 Expression of heavy subunit of gamma-glutamylcysteine synthetase (gamma-GCSh) in human colorectal carcinoma. International journal of cancer 25 11774239
2018 GCSH antisense regulation determines breast cancer cells' viability. Scientific reports 22 30337557
2002 Heterozygous GLDC and GCSH gene mutations in transient neonatal hyperglycinemia. Annals of neurology 20 12402263
2021 PLEK2, RRM2, GCSH: A Novel WWOX-Dependent Biomarker Triad of Glioblastoma at the Crossroads of Cytoskeleton Reorganization and Metabolism Alterations. Cancers 17 34204789
2023 Pathogenic variants in GCSH encoding the moonlighting H-protein cause combined nonketotic hyperglycinemia and lipoate deficiency. Human molecular genetics 12 36190515
2021 Biallelic start loss variant, c.1A > G in GCSH is associated with variant nonketotic hyperglycinemia. Clinical genetics 7 33890291
2023 Integrated analysis reveals a potential cuproptosis-related ceRNA axis SNHG17/miR-29a-3p/GCSH in prostate adenocarcinoma. Heliyon 4 38027603
2016 Mutation analysis of GLDC, AMT and GCSH in cataract captive-bred vervet monkeys (Chlorocebus aethiops). Journal of medical primatology 4 27325422
2026 GCSH promotes colorectal cancer progression by inhibiting Cuproptosis through the PI3K/AKT-FDX1 axis. Functional & integrative genomics 0 41591502
2026 GCSH promotes MASH progression by regulating cuproptosis through the glycine-GSH metabolic pathway. Free radical biology & medicine 0 42082057
2026 Multiomics Characterization of GCSH + Macrophages Reveals Therapeutic Vulnerabilities and Immune-Metabolic Crosstalk in Triple-Negative Breast Cancer. Human mutation 0 42111497

Missed literature

Know a paper Affinage missed for GCSH? Flag it for the maintainers and the community.

No submissions yet.