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Showing CHCHD3MIC19 is a alias.

CHCHD3

MICOS complex subunit MIC19 · UniProt Q9NX63

Length
227 aa
Mass
26.2 kDa
Annotated
2026-06-09
16 papers in source corpus 13 papers cited in narrative 13 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

CHCHD3 (Mic19) is a peripheral protein of the mitochondrial inner membrane facing the intermembrane space that functions as a scaffolding subunit organizing crista junction architecture and supporting oxidative metabolism (PMID:21081504). It is imported into the IMS through a two-signal mechanism: N-terminal myristoylation directs binding to the outer membrane, while its C-terminal CHCH domain mediates translocation and is captured by a Mia40-dependent disulfide relay (Cys193–Mia40 Cys55), and the four CHCH cysteines are required for folding and partner binding rather than import itself (PMID:23019327, PMID:30427857). Once oxidized, the intramolecular disulfide-bonded form selectively engages Mic60 to drive MICOS assembly and proper inner membrane morphology (PMID:26416881). CHCHD3 directly bridges the outer-membrane Sam50 and inner-membrane Mic60 to form the Sam50-Mic19-Mic60 axis that unites the SAM and MICOS complexes into the MIB supercomplex and maintains crista junctions and ATP production (PMID:31097788); this axis is dismantled when OMA1 cleaves CHCHD3 at its N-terminus under stress (PMID:31097788) or when SLC25A6 competitively displaces CHCHD3 from Mic60, causing MICOS disruption and mitochondrial fission (PMID:42020360). Beyond cristae shaping, CHCHD3 organizes ER-mitochondria contact sites via an EMC2-SLC25A46-Mic19 axis to support mitochondrial lipid metabolism and fatty acid β-oxidation, and hepatic loss spontaneously triggers NASH and liver fibrosis that is reversed by re-expression (PMID:38168065). Its abundance is set post-translationally by ASB1-mediated K48 ubiquitination driving degradation and by USP3-mediated K48 deubiquitination that stabilizes it under hypoxia downstream of HIF-1α, with both axes implicated in cancer cell proliferation through ROS signaling (PMID:39113857, PMID:40770539).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 2007 Medium

    Before any mitochondrial role was known, CHCHD3 was identified as a phosphorylation substrate, providing the first molecular handle on the protein.

    Evidence Chemical-genetic analog-sensitive PKA with N6-substituted ATP analogs and MS substrate identification

    PMID:17242405

    Open questions at the time
    • Phosphosite(s) on CHCHD3 not mapped to a function
    • No link established between PKA phosphorylation and MICOS/cristae roles
    • Single in vitro study
  2. 2010 High

    Established CHCHD3 as a structural scaffold of the inner membrane whose loss collapses crista architecture and destabilizes import/morphology complexes, defining its core cellular role.

    Evidence RNAi in HeLa cells with Co-IP partner mapping, EM ultrastructure, and metabolic flux measurements

    PMID:21081504

    Open questions at the time
    • Mechanism of how scaffolding stabilizes partners not resolved
    • Direct vs indirect nature of OPA1 effect unclear
    • Import-relay details not addressed
  3. 2012 High

    Resolved how CHCHD3 reaches the IMS, separating the myristoylation-dependent membrane-binding step from CHCH-domain-mediated translocation and the Mia40 disulfide relay.

    Evidence Cysteine and G2A mutagenesis with in vitro import and Mia40/mitofilin/Sam50 binding assays

    PMID:23019327

    Open questions at the time
    • In vivo myristoyltransferase not identified here
    • Redox state of mature protein in cells not quantified
    • How cysteine oxidation gates partner binding unresolved
  4. 2015 High

    Showed that the oxidized, disulfide-bonded form of CHCHD3 is the species that binds Mic60, linking redox state to MICOS assembly competence.

    Evidence Non-reducing SDS-PAGE redox analysis, MIA pathway mutants, and reciprocal Co-IP in yeast and human cells

    PMID:26416881

    Open questions at the time
    • Stimuli that shift CHCHD3 redox state in vivo unknown
    • Quantitative contribution of oxidation to morphology not isolated
    • Reductase/regulators not identified
  5. 2017 High

    Pinpointed CHCHD3 to crista junctions at nanoscale resolution and associated it with respiratory machinery, anchoring its function spatially.

    Evidence miniSOG/APEX2 genetic EM tagging and electron tomography in cardiac and astrocyte lines

    PMID:28808085

    Open questions at the time
    • Functional consequence of cytochrome c oxidase subunit IV association untested
    • Dynamics of localization not captured
    • Cell-type generality beyond two lines unaddressed
  6. 2019 High

    Defined the Sam50-Mic19-Mic60 axis as the physical bridge connecting SAM and MICOS into the MIB supercomplex and showed OMA1 cleavage as a stress-responsive off-switch controlling crista junctions and ATP output.

    Evidence Reciprocal Co-IP, OMA1 cleavage assays, MIB supercomplex analysis, ATP and EM cristae readouts

    PMID:31097788

    Open questions at the time
    • Trigger and regulation of OMA1 cleavage of CHCHD3 not fully defined
    • Stoichiometry of the axis unresolved
    • Structural basis of bridging not determined
  7. 2023 Medium

    Connected CHCHD3-driven cristae formation to whole-organism physiology, showing fasting-induced upregulation reprograms hepatic respiration and a uracil-UPP2 signaling output.

    Evidence Mouse liver proteomics, hepatic transgenic overexpression, respirometry, and metabolite profiling

    PMID:37473754

    Open questions at the time
    • Mechanism coupling cristae density to UPP2 activity unresolved
    • Generality beyond liver unknown
    • Single-lab in vivo model
  8. 2024 High

    Extended CHCHD3 function beyond cristae to ER-mitochondria contact organization via an EMC2-SLC25A46-Mic19 axis required for lipid metabolism, with hepatic loss causing reversible NASH.

    Evidence Liver-specific conditional knockout with rescue, contact-site quantification, fatty acid oxidation assays

    PMID:38168065

    Open questions at the time
    • Molecular detail of how the axis tethers ER and mitochondria not resolved
    • Relationship between MICOS and contact-site roles unclear
    • Direct EMC2/SLC25A46 binding interfaces undefined
  9. 2024 Medium

    Identified ASB1 as an E3 ligase that destabilizes CHCHD3 via K48 ubiquitination, placing CHCHD3 abundance under proteostatic control with consequences for ROS and tumor cell behavior.

    Evidence Interactome MS, Co-IP, cycloheximide chase, ubiquitination and rescue assays in prostate cancer cells

    PMID:39113857

    Open questions at the time
    • Ubiquitinated residues on CHCHD3 not mapped
    • How stabilized CHCHD3 activates ROS signaling unresolved
    • Single-lab study
  10. 2025 Medium

    Showed the opposing arm of CHCHD3 proteostasis: hypoxic HIF-1α induces USP3, which deubiquitinates and stabilizes CHCHD3 to promote tumor progression.

    Evidence ChIP for HIF-1α at the USP3 promoter, USP3-MIC19 Co-IP, ubiquitination assays, and xenograft model

    PMID:40770539

    Open questions at the time
    • Deubiquitination site specificity not mapped
    • Whether USP3 and ASB1 act on the same lysines unknown
    • Single-lab study
  11. 2026 Medium

    Demonstrated a competitive regulatory mechanism in which SLC25A6 binds Mic60 and displaces CHCHD3, linking metabolic stress to MICOS disassembly and fission.

    Evidence Competitive Co-IP and T126A site-directed mutagenesis with morphology and apoptosis assays

    PMID:42020360

    Open questions at the time
    • Physiological conditions favoring SLC25A6 over CHCHD3 binding undefined
    • Structural basis of competition unresolved
    • Single-lab study
  12. 2026 Low

    Reported additional CHCHD3 binding partners (SAMM50, VDAC1/2) coupling its loss to impaired energy metabolism and ROS in lung adenocarcinoma.

    Evidence IP-MS and Co-IP with Seahorse, ROS, cell cycle, and apoptosis assays in LUAD cells

    PMID:42261148

    Open questions at the time
    • VDAC1/2 interaction validated by a single Co-IP/IP-MS without reciprocal or functional dissection
    • Direct vs supercomplex-mediated binding to VDAC unclear
    • Single-lab study

Open questions

Synthesis pass · forward-looking unresolved questions
  • How the multiple post-translational controls (PKA phosphorylation, Mia40 oxidation, OMA1 cleavage, ASB1/USP3 ubiquitination) are integrated to set CHCHD3 levels and partner choice across physiological states remains unresolved.
  • No integrated model linking redox, phosphorylation, and ubiquitination states
  • Functional role of PKA phosphorylation never connected to MICOS/cristae
  • Structural model of the Sam50-Mic19-Mic60 axis lacking

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 3 GO:0005198 structural molecule activity 2
Localization
GO:0005739 mitochondrion 3
Pathway
R-HSA-1430728 Metabolism 2 R-HSA-1852241 Organelle biogenesis and maintenance 2 R-HSA-392499 Metabolism of proteins 2
Complex memberships
MIB supercomplexMICOSSam50-Mic19-Mic60 axis

Evidence

Reading pass · 13 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2010 ChChd3 (CHCHD3/Mic19) is a peripheral protein of the mitochondrial inner membrane facing the intermembrane space. RNAi knockdown in HeLa cells caused mitochondrial fragmentation, reduced OPA1 protein levels, impaired fusion, and aberrant cristae with reduced crista junction opening diameter (~50% reduction). ChChd3 interacts with inner membrane proteins mitofilin and OPA1, and outer membrane protein Sam50; knockdown led to near-complete loss of mitofilin and Sam50, establishing ChChd3 as a scaffolding protein stabilizing complexes that maintain crista architecture and protein import. RNAi knockdown in HeLa cells, Co-IP/binding partner analysis, ultrastructural analysis (electron microscopy), oxygen consumption and glycolytic rate measurements The Journal of biological chemistry High 21081504
2007 CHCHD3 (ChChd3) was identified as a novel substrate of cAMP-dependent protein kinase (PKA) using an analog-sensitive PKA catalytic subunit (M120G mutant) with bulky N6-substituted ATP analogs, establishing PKA as a writer of CHCHD3 phosphorylation. Chemical genetics approach with analog-sensitive PKA catalytic subunit, in vitro kinase assay with N6-substituted ATP analogs, mass spectrometry substrate identification The Journal of biological chemistry Medium 17242405
2012 CHCHD3 import into the mitochondrial IMS requires both N-terminal myristoylation and the C-terminal CHCH domain. Myristoylation promotes binding to the outer membrane; the CHCH domain mediates translocation across the outer membrane. The disulfide relay via Mia40 occurs preferentially between Cys193 (second cysteine in helix 1) and Mia40 Cys55. Each of the four CHCH domain cysteines is essential for protein folding and binding to mitofilin and Sam50, but not for import per se. Cysteine mutagenesis, myristoylation site mutagenesis (G2A), in vitro import assays, binding assays to Mia40/mitofilin/Sam50, subcellular fractionation The Journal of biological chemistry High 23019327
2015 MIC19 (CHCHD3) undergoes oxidation in mitochondria and requires the MIA pathway for mitochondrial localization. Yeast Mic19 exists in two redox forms; the intramolecular disulfide-bonded form is specifically bound to Mic60 of the MICOS complex. Mic19 oxidation is not essential for MICOS integration but promotes MICOS assembly and proper inner membrane morphology. Redox state analysis (non-reducing SDS-PAGE), MIA pathway mutant analysis, Co-IP (Mic19-Mic60 interaction), yeast genetics, immunofluorescence Molecular and cellular biology High 26416881
2017 Using genetically encoded tags (miniSOG and APEX2) and electron tomography, Mic19 (CHCHD3) was localized at nanoscale resolution to crista junctions, distributed in a network along the mitochondrial periphery, and enriched inside cristae in cardiac and astrocyte cell lines. Mic19 was found associated with cytochrome c oxidase subunit IV at crista junctions. Genetic tagging with miniSOG and APEX2, electron tomography, subcellular fractionation Journal of cell science High 28808085
2018 MIC19 (CHCHD3) is N-myristoylated at its N-terminus. In vitro and in vivo metabolic labeling confirmed N-myristoylation. G2A (non-myristoylated) mutant analysis showed that myristoylation is required for proper mitochondrial targeting and membrane binding of MIC19. Additionally, myristoylation of MIC19 is required for the protein-protein interaction between MIC19 and SAMM50. In vitro and in vivo metabolic labeling with myristate, G2A mutagenesis, immunofluorescence, subcellular fractionation, co-immunoprecipitation PloS one High 30427857
2019 Mic19 (CHCHD3) directly interacts with outer membrane protein Sam50 and inner membrane protein Mic60 to form the Sam50-Mic19-Mic60 axis, which connects SAM and MICOS complexes to assemble the MIB supercomplex and mediates mitochondrial outer-inner membrane contact. OMA1 protease cleaves Mic19 at its N-terminus under physiological stress, disrupting this axis and causing loss of crista junctions, abnormal cristae distribution, and reduced ATP production. Sam50 acts as an anchoring point at the outer membrane guiding crista junction formation. Co-IP, OMA1-mediated cleavage assays, MIB supercomplex analysis, ATP production measurements, mitochondrial morphology analysis, electron microscopy of cristae Cell death and differentiation High 31097788
2023 Fasting induces MIC19 (CHCHD3) upregulation in mouse liver, promoting cristae formation. Enforced hepatic MIC19 expression promotes mitochondrial respiration, fatty acid oxidation, and suppresses gluconeogenesis. MIC19-driven cristae formation increases uridine phosphorylase UPP2 activity and uracil accumulation, which signals to promote locomotion. Comparative mouse proteomics, hepatic MIC19 transgenic overexpression, Seahorse respirometry, metabolite profiling, dietary uracil supplementation experiments Cell metabolism Medium 37473754
2024 Mic19 (CHCHD3) regulates ER-mitochondria contacts through the EMC2-SLC25A46-Mic19 axis. Liver-specific Mic19 knockout in mice leads to reduction of ER-mitochondrial contacts, mitochondrial lipid metabolism disorder, disorganization of mitochondrial cristae, and mitochondrial unfolded protein stress response in hepatocytes, impairing fatty acid β-oxidation and spontaneously triggering NASH and liver fibrosis. Re-expression of Mic19 in LKO hepatocytes rescued liver disease. Liver-specific conditional knockout (LKO), ER-mitochondria contact site quantification, mitochondrial fractionation, fatty acid oxidation assays, hepatic rescue re-expression experiments, in vivo mouse models Nature communications High 38168065
2024 ASB1 E3 ubiquitin ligase interacts with CHCHD3 and promotes its degradation via K48-linked ubiquitination. Loss of ASB1 stabilizes CHCHD3, which activates ROS signaling to promote prostate cancer cell proliferation, clonogenicity, and migration. Quantitative mass spectrometry interactome analysis, co-immunoprecipitation, cycloheximide chase assay, ubiquitination assay, cell rescue experiments American journal of cancer research Medium 39113857
2025 Under hypoxic conditions, HIF-1α binds the USP3 promoter to upregulate USP3 expression, which in turn stabilizes MIC19 (CHCHD3) through K48-linked deubiquitination, preventing its proteasomal degradation and promoting NSCLC progression. ChIP assay (HIF-1α at USP3 promoter), ubiquitination assay, co-immunoprecipitation (USP3-MIC19), in vitro cell proliferation/invasion assays, in vivo xenograft mouse model Acta pharmacologica Sinica Medium 40770539
2026 SLC25A6 directly interacts with MIC60 and competitively inhibits MIC19 (CHCHD3) binding to MIC60, disrupting the MICOS complex. A SLC25A6 T126A mutant failed to bind MIC60, abrogating its ability to destabilize MICOS and cause mitofission. This mechanistically links metabolic stress to mitochondrial fragmentation via displacement of MIC19 from MIC60. Co-immunoprecipitation (SLC25A6-MIC60, competitive with MIC19), site-directed mutagenesis (T126A), mitochondrial morphology analysis, apoptosis assays Cell death & disease Medium 42020360
2026 CHCHD3 knockdown in lung adenocarcinoma cells impaired mitochondrial energy metabolism and caused excessive ROS production. IP-MS and Co-IP validated SAMM50 and VDAC1/2 as direct CHCHD3 binding partners, with disruption of these interactions linked to ROS accumulation. IP-MS, co-immunoprecipitation, Seahorse metabolic analysis, ROS measurement, cell cycle analysis, apoptosis assays Anti-cancer agents in medicinal chemistry Low 42261148

Source papers

Stage 0 corpus · 16 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2010 ChChd3, an inner mitochondrial membrane protein, is essential for maintaining crista integrity and mitochondrial function. The Journal of biological chemistry 281 21081504
2019 Sam50-Mic19-Mic60 axis determines mitochondrial cristae architecture by mediating mitochondrial outer and inner membrane contact. Cell death and differentiation 92 31097788
2024 Mic19 depletion impairs endoplasmic reticulum-mitochondrial contacts and mitochondrial lipid metabolism and triggers liver disease. Nature communications 71 38168065
2012 Targeting and import mechanism of coiled-coil helix coiled-coil helix domain-containing protein 3 (ChChd3) into the mitochondrial intermembrane space. The Journal of biological chemistry 64 23019327
2015 The Oxidation Status of Mic19 Regulates MICOS Assembly. Molecular and cellular biology 53 26416881
2007 Identification of ChChd3 as a novel substrate of the cAMP-dependent protein kinase (PKA) using an analog-sensitive catalytic subunit. The Journal of biological chemistry 40 17242405
2023 Liver mitochondrial cristae organizing protein MIC19 promotes energy expenditure and pedestrian locomotion by altering nucleotide metabolism. Cell metabolism 26 37473754
2018 Identification and characterization of protein N-myristoylation occurring on four human mitochondrial proteins, SAMM50, TOMM40, MIC19, and MIC25. PloS one 26 30427857
2017 Sub-mitochondrial localization of the genetic-tagged mitochondrial intermembrane space-bridging components Mic19, Mic60 and Sam50. Journal of cell science 26 28808085
2012 Cloning and functional analysis of FLJ20420: a novel transcription factor for the BAG-1 promoter. PloS one 13 22567091
2023 MIC19 Exerts Neuroprotective Role via Maintaining the Mitochondrial Structure in a Rat Model of Intracerebral Hemorrhage. International journal of molecular sciences 5 37511310
2024 ASB1 inhibits prostate cancer progression by destabilizing CHCHD3 via K48-linked ubiquitination. American journal of cancer research 3 39113857
2024 Up-regulation of MIC19 promotes growth and metastasis of hepatocellular carcinoma by activating ROS/NF-κB signaling. Translational oncology 1 38350286
2026 Glutamine metabolic stress induces SLC25A6-dependent mitofission via MIC60-MIC19 complex disassembly in colorectal cancer. Cell death & disease 0 42020360
2026 Targeting CHCHD3 inhibits tumorigenesis of NSCLC by Reprogramming Mitochondrial Metabolism. Anti-cancer agents in medicinal chemistry 0 42261148
2025 USP3 stabilizes MIC19 by deubiquitination under hypoxic stress and promotes the progression of non-small cell lung cancer. Acta pharmacologica Sinica 0 40770539

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