Affinage

RHOT2

Mitochondrial Rho GTPase 2 · UniProt Q8IXI1

Length
618 aa
Mass
68.1 kDa
Annotated
2026-06-10
18 papers in source corpus 14 papers cited in narrative 14 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

RHOT2/Miro2 is an outer mitochondrial membrane Rho-like GTPase that functions as a multifunctional adaptor coordinating mitochondrial positioning, trafficking, and turnover (PMID:30111583, PMID:42102968). Through its N-terminal GTPase domain it recruits and stabilizes myosin XIX (Myo19), and the nucleotide state of this domain governs both Myo19 association and the broader Miro2 proximity interaction network (PMID:30111583, PMID:42102968); the GTP-bound nGTPase domain has been characterized structurally by NMR and closely resembles that of Miro1 (PMID:36050579). Miro2 supports cytoskeleton-based mitochondrial movement and inter-mitochondrial communication, promoting nanotunneling and kissing along microtubules in cardiomyocytes (PMID:31455181), and isoform-specifically driving mitochondrial motility in pancreatic alpha cells to enable glucose-regulated glucagon secretion (PMID:41308986). During mitochondrial quality control, Miro2 acts as a regulatory platform: PINK1-mediated phosphorylation at Ser325/Ser430 and Ca2+ binding to its EF2 domain drive its demultimerization and realignment, which are required for Parkin translocation to damaged mitochondria, while Parkin-mediated ubiquitination targets Miro2 for proteasomal degradation under hypertrophic stress (PMID:36659543, PMID:31455181). Miro2 negatively regulates Drp1-dependent fission, acting upstream of Drp1 to preserve mitochondrial integrity, and also localizes to peroxisomes via a Pex19-dependent transmembrane interaction to restrain peroxisomal fission (PMID:33575111, PMID:31894645). Its function is tuned by CBS/H2S-mediated sulfhydration of cysteines C185 and C504, which sustains mitochondrial dynamics and trophoblast motility (PMID:39461943). In cancer, Miro2 promotes invasion and metastasis by cooperating with MYO9B to suppress RhoA activity, relays GCN2/ATF4 stress signaling through interaction with GCN1, and mediates mitochondrial transfer from cancer cells to fibroblasts to drive cancer-associated fibroblast differentiation (PMID:39723893, PMID:34992146, PMID:40877413).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 2018 High

    Establishing how mitochondria engage actin-based motors, Miro2 was identified as a mitochondrial receptor for myosin XIX whose recruitment and Myo19 stability are governed by its N-terminal GTPase domain nucleotide state.

    Evidence Proximity labeling, direct pulldown, and in vivo recruitment/downregulation assays of Miro1/2 and Myo19

    PMID:30111583

    Open questions at the time
    • Did not resolve how GTP loading is regulated on the mitochondrial membrane
    • Functional consequence of Miro2-specific (vs Miro1) Myo19 recruitment unresolved
  2. 2019 High

    To define Miro2's role in cardiac mitochondrial communication and turnover, it was shown to promote nanotunneling/kissing and to be degraded by Parkin-mediated ubiquitination under hypertrophic stress.

    Evidence Adenoviral overexpression, transgenic mice, photoactivatable-GFP communication assays, proteasome inhibition, Parkin overexpression

    PMID:31455181

    Open questions at the time
    • Site of Parkin ubiquitination on Miro2 not mapped
    • Relationship between communication function and degradation not integrated
  3. 2019 High

    Addressing how Miro2 participates in mitophagy, PINK1 phosphorylation (Ser325/Ser430) and Ca2+ binding at the EF2 domain were shown to drive demultimerization required for Parkin translocation.

    Evidence CCCP treatment, phospho-site and Ca2+-domain mutagenesis, Parkin translocation assays, Miro2 knockout mouse phenotyping

    PMID:36659543

    Open questions at the time
    • Structural basis of tetramer-to-monomer transition not resolved
    • Whether demultimerization precedes or follows Miro2 degradation unclear
  4. 2020 High

    Extending Miro localization beyond mitochondria, Miro1/2 were found at peroxisomes where they restrain Drp1-dependent peroxisomal fission via a Pex19-dependent transmembrane interaction.

    Evidence Localization studies, knockdown/knockout with peroxisomal morphology readout, Pex19 interaction assays, domain mapping

    PMID:31894645

    Open questions at the time
    • Partitioning between mitochondria and peroxisomes not quantified
    • Mechanism of Drp1 suppression at peroxisomes not defined
  5. 2020 Medium

    Linking Miro2 loss to mitochondrial dysfunction, knockdown in neural progenitors caused excessive fragmentation and PINK1/Parkin mitophagy, placing Miro2 upstream of Drp1-dependent fission.

    Evidence miR-351-5p targeting, siRNA knockdown with adenoviral rescue, Mdivi-1 epistasis, morphology/function assays

    PMID:33575111

    Open questions at the time
    • Direct molecular link between Miro2 and Drp1 not established
    • Cell-type generality untested
  6. 2022 Medium

    To probe Miro2 in cancer signaling, it was shown to bind GCN1 and to be required for GCN2/ATF4 stress-signaling-driven prostate cancer growth.

    Evidence Co-IP, binding-partner network analysis, functional mutagenesis (159L), siRNA, xenografts

    PMID:34992146

    Open questions at the time
    • Reciprocal validation and direct binding interface not shown
    • How a mitochondrial protein couples to GCN1 translational stress signaling unclear
  7. 2022 Medium

    Providing a structural foundation, the GTP-bound N-terminal GTPase domain of human Miro2 was assigned by NMR and shown to closely resemble the Miro1 nGTPase fold.

    Evidence NMR backbone chemical shift assignments (residues 1–180) and comparison with Miro1 crystal structure

    PMID:36050579

    Open questions at the time
    • No functional mutagenesis in this study
    • Full-length and EF-hand/second GTPase domain architecture not determined
  8. 2024 Medium

    Defining a Miro2-dependent invasion mechanism, Miro2 was shown to cooperate with MYO9B to suppress RhoA, with dual MIRO2/RhoA ablation rescuing invasion.

    Evidence siRNA, double-gene ablation rescue, invasion assays, metastasis models, RhoA activity assays

    PMID:39723893

    Open questions at the time
    • Whether Miro2 directly modulates MYO9B GAP activity unknown
    • Mechanistic link from mitochondrial Miro2 to cytosolic RhoA regulation undefined
  9. 2024 Medium

    Identifying redox tuning of Miro2, CBS-derived H2S sulfhydrates C185/C504 to sustain mitochondrial dynamics and trophoblast motility.

    Evidence CBS knockdown, GYY4137 H2S donor, C185S/C504S double mutant, morphology and invasion/migration assays

    PMID:39461943

    Open questions at the time
    • Single lab, single study
    • How sulfhydration alters Miro2 conformation or partner binding not defined
  10. 2025 Medium

    Demonstrating tissue-specific motility roles, Miro2 (but not Miro1) was shown to drive mitochondrial motility in pancreatic alpha cells and enable glucose-induced suppression of glucagon secretion.

    Evidence Isoform-selective siRNA, mitochondrial motility imaging, glucagon/insulin secretion and ATP/ADP measurements

    PMID:41308986

    Open questions at the time
    • Mechanism of Miro1/Miro2 functional divergence in alpha cells unknown
    • Single lab, single study
  11. 2025 Medium

    Connecting Miro2 to tumor microenvironment remodeling, cancer-cell MIRO2 was shown to be required for mitochondrial transfer to fibroblasts and CAF differentiation.

    Evidence MIRO2 depletion in cancer cells, co-culture and xenograft assays, transfer quantification, CAF marker analysis

    PMID:40877413

    Open questions at the time
    • Route of intercellular mitochondrial transfer not defined
    • Whether Miro2 acts in donor trafficking machinery directly unclear
  12. 2026 Medium

    Reinforcing the nucleotide-state control of Miro2's interactome, proximity proteomics with the GTP-binding mutant T18N showed reduced proximal proteins and Myo19 destabilization, and identified CISD1 as a trafficking partner.

    Evidence TurboID proximity labeling with mass spectrometry, T18N mutant comparison, Co-IP, knockdown and differentiation assays

    PMID:41663665 PMID:42102968

    Open questions at the time
    • CISD1 interaction rests on single Co-IP with partial rescue
    • Functional contribution of individual proximal proteins not dissected

Open questions

Synthesis pass · forward-looking unresolved questions
  • How Miro2 mechanistically transmits its outer-membrane adaptor function to cytosolic outputs such as RhoA regulation and GCN1/ATF4 signaling, and how its many post-translational modifications are integrated, remains unresolved.
  • No structural model of full-length Miro2 with bound effectors
  • Integration of phosphorylation, ubiquitination, and sulfhydration codes not mapped
  • Mechanism coupling mitochondrial Miro2 to cytosolic signaling pathways unknown

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0003924 GTPase activity 3 GO:0098772 molecular function regulator activity 3 GO:0060090 molecular adaptor activity 2
Localization
GO:0005739 mitochondrion 4 GO:0005777 peroxisome 1
Pathway
R-HSA-1643685 Disease 3 R-HSA-1852241 Organelle biogenesis and maintenance 3 R-HSA-9612973 Autophagy 2
Partners
CISD1GCN1MYO19MYO9BPARK2PEX19PINK1

Evidence

Reading pass · 14 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2018 Miro1 and Miro2 were identified as mitochondrial receptors for myosin XIX (Myo19); Miro1 binds directly to a C-terminal fragment of the Myo19 tail region, and Miro1/2 recruit the Myo19 tail in vivo. This recruitment is regulated by the nucleotide state of the N-terminal Rho-like GTPase domain of Miro1/2. Myo19 protein stability in cells depends on its association with Miro1/2. Proximity labelling, direct interaction/pulldown studies, in vivo recruitment assays, downregulation experiments Journal of cell science High 30111583
2020 Miro1 and Miro2 localize to peroxisomes (in addition to mitochondria), where they negatively regulate Drp1-dependent peroxisomal fission to maintain peroxisomal size and morphology. Peroxisomal localization of Miro is regulated by its first GTPase domain and mediated by an interaction of its transmembrane domain with the peroxisomal-membrane protein chaperone Pex19. Localization studies, genetic knockdown/knockout with peroxisomal morphology readout, interaction assays (Pex19 binding) EMBO reports High 31894645
2019 Miro2 regulates inter-mitochondrial communication in cardiomyocytes by promoting mitochondrial nanotunneling and kissing along microtubules. Parkin-mediated ubiquitination leads to degradation of Miro2, and proteasome inhibition blocked phenylephrine-induced decrease of Miro2, establishing Parkin as the E3 ubiquitin ligase that targets Miro2 for degradation during hypertrophic stress. Adenovirus-mediated overexpression, transgenic mice, mitochondria-targeted photoactivatable GFP for communication assay, proteasome inhibition, Parkin overexpression Circulation research High 31455181
2019 Miro2 undergoes CCCP-induced demultimerization from a tetramer to a monomer and changes mitochondrial localization (realignment). This realignment is regulated by PINK1-mediated phosphorylation at Ser325/Ser430 and by Ca2+ binding to the EF2 domain, both of which are required for subsequent Parkin translocation to damaged mitochondria during mitophagy. CCCP treatment, phosphorylation site mutagenesis, Ca2+ binding domain analysis, mitophagy/Parkin translocation assays, Miro2 knockout mouse phenotyping Science bulletin High 36659543
2022 MIRO2 interacts with General Control Nonderepressible 1 (GCN1) in prostate cancer cells, and this interaction is necessary for efficient GCN1-mediated GCN2 kinase signaling and induction of ATF4. MIRO2 mutation 159L increases GCN1 binding. MIRO2's effect on prostate cancer cell growth is mediated through ATF4. Co-immunoprecipitation, network analysis of binding partners, functional mutagenesis (MIRO2 159L), siRNA knockdown, xenograft tumor models Molecular cancer research : MCR Medium 34992146
2020 miR-351-5p targets Miro2 in hippocampal neural progenitor cells; Miro2 knockdown induces excessive mitochondrial fragmentation, mitochondrial dysfunction (decreased membrane potential, increased ROS), and cell death with subsequent PINK1/Parkin-mediated mitophagy induction. Suppression of mitochondrial fission by Mdivi-1 completely inhibited miR-351-5p-induced cell death, placing Miro2 upstream of Drp1-dependent fission. siRNA knockdown, adenovirus rescue, Mdivi-1 pharmacological inhibition, mitochondrial morphology and function assays Molecular therapy. Nucleic acids Medium 33575111
2024 MIRO2 supports tumor cell invasion and metastasis through cooperation with unconventional myosin 9B (MYO9B); depletion of MIRO2 phenocopies MYO9B depletion (reduced invasion and increased active RhoA), and dual ablation of MIRO2 and RhoA fully rescues tumor cell invasion. MIRO2 is required for MYO9B-driven invasion. siRNA knockdown, double-gene ablation (MIRO2 + RhoA), in vitro invasion assays, mouse metastasis models, RhoA activity assays Cell reports Medium 39723893
2024 Miro2 cysteines C185 and C504 are sulfhydrated by CBS-derived H2S; this sulfhydration is required for maintenance of mitochondrial dynamics and for trophoblast invasion and migration. Double mutation of Miro2 C185/C504 to serine fragmented mitochondria and inhibited invasion/migration that could not be rescued by H2S donor treatment. CBS knockdown, H2S donor (GYY4137) treatment, site-directed mutagenesis (C185S/C504S double mutant), mitochondrial morphology assays, invasion/migration assays Cell death & disease Medium 39461943
2025 Knockdown of Miro2, but not Miro1, reduces mitochondrial motility specifically in pancreatic alpha cells and impairs glucose-induced inhibition of glucagon secretion, without affecting insulin secretion or mitochondrial motility in non-alpha islet cells. Under low glucose, mitochondria are arrested in positions further from the nucleus, correlating with increased ATP/ADP in the sub-plasma membrane space. siRNA knockdown of Miro2 vs Miro1, mitochondrial motility imaging, glucagon/insulin secretion assays, ATP/ADP measurements The Journal of biological chemistry Medium 41308986
2025 MIRO2 in cancer cells is required for mitochondrial transfer to fibroblasts; depletion of MIRO2 in cancer cells suppresses mitochondrial transfer and inhibits cancer-associated fibroblast (CAF) differentiation and tumor growth. MIRO2 depletion in cancer cells, co-culture and xenograft assays, mitochondrial transfer quantification, CAF marker analysis Nature cancer Medium 40877413
2022 NMR backbone resonance assignments of the N-terminal GTPase (nGTPase) domain of human Miro2 bound to GTP were determined for residues 1–180, confirming that the overall secondary structure closely resembles that of Miro1 nGTPase bound to GTP, with minor variations attributable to crystal packing in the Miro1 structure. NMR spectroscopy (backbone chemical shift assignments), structural comparison with Miro1 crystal structure Biomolecular NMR assignments Medium 36050579
2018 NOS3 inhibition in glial cells preserves Miro-2 levels and prevents axonal mitochondrial fission and restores mitochondrial motility following oxygen-glucose deprivation in white matter, providing post-ischemic protection to both young and aging axons. Pharmacological NOS3 inhibition, genetic NOS3 deletion, electrophysiology, 3D electron microscopy, Miro-2 level quantification The Journal of neuroscience Low 29891729
2026 Proximity labeling (TurboID) of Miro2 in hippocampal neural stem cells identified CISD1 as a significant interaction partner. Knockdown of both Miro2 and CISD1 impairs mitochondrial trafficking and disrupts stem cell differentiation with increased cytotoxicity. Rescue experiments partially reversed cell death, and both proteins show increased expression and interaction during differentiation. TurboID proximity labeling, Co-IP, siRNA knockdown, mitochondrial trafficking assays, differentiation assays Communications biology Low 41663665
2026 TurboID proximity labeling of Miro2 and its GTP-binding mutant Miro2 T18N showed that abolishing GTP-binding to the N-terminal GTPase domain considerably reduces the number of proteins in proximity of Miro2, demonstrating that the nucleotide state of the N-terminal GTPase domain governs the interaction network and stabilization of Myo19. TurboID proximity labeling followed by mass spectrometry, GTP-binding mutant (T18N) comparison, cell cycle stage analysis (interphase vs prometaphase) Molecular & cellular proteomics : MCP Medium 42102968

Source papers

Stage 0 corpus · 18 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2018 Identification of Miro1 and Miro2 as mitochondrial receptors for myosin XIX. Journal of cell science 89 30111583
2020 Miro2 tethers the ER to mitochondria to promote mitochondrial fusion in tobacco leaf epidermal cells. Communications biology 43 32246085
2020 Peroxisomal fission is modulated by the mitochondrial Rho-GTPases, Miro1 and Miro2. EMBO reports 40 31894645
2019 Miro2 Regulates Inter-Mitochondrial Communication in the Heart and Protects Against TAC-Induced Cardiac Dysfunction. Circulation research 37 31455181
2020 miR-351-5p/Miro2 axis contributes to hippocampal neural progenitor cell death via unbalanced mitochondrial fission. Molecular therapy. Nucleic acids 25 33575111
2022 MIRO2 Regulates Prostate Cancer Cell Growth via GCN1-Dependent Stress Signaling. Molecular cancer research : MCR 22 34992146
2018 NOS3 Inhibition Confers Post-Ischemic Protection to Young and Aging White Matter Integrity by Conserving Mitochondrial Dynamics and Miro-2 Levels. The Journal of neuroscience : the official journal of the Society for Neuroscience 18 29891729
2025 MIRO2-mediated mitochondrial transfer from cancer cells induces cancer-associated fibroblast differentiation. Nature cancer 13 40877413
2012 Genetic Screening of the Mitochondrial Rho GTPases MIRO1 and MIRO2 in Parkinson's Disease. The open neurology journal 10 22496713
2024 Miro2 sulfhydration by CBS/H2S promotes human trophoblast invasion and migration via regulating mitochondria dynamics. Cell death & disease 9 39461943
2019 Miro2 supplies a platform for Parkin translocation to damaged mitochondria. Science bulletin 9 36659543
2020 The role of RHOT1 and RHOT2 genetic variation on Parkinson disease risk and onset. Neurobiology of aging 7 32948353
2024 MIRO2 promotes cancer invasion and metastasis via MYO9B suppression of RhoA activity. Cell reports 4 39723893
2004 Cloning and characterization of the mouse Arht2 gene which encodes a putative atypical GTPase. Cytogenetic and genome research 4 15218247
2026 Proximity labeling unveils potential roles of the Miro2-CISD1 network in mitochondrial dynamics and neuronal differentiation. Communications biology 0 41663665
2026 Dynamic Proximity Networks of Myosin-19 (Myo19) and its Mitochondrial Receptors Miro2 and Metaxin-3. Molecular & cellular proteomics : MCP 0 42102968
2025 Mitochondrial movement in pancreatic alpha cells requires Miro2 and is regulated by glucose. The Journal of biological chemistry 0 41308986
2022 NMR resonance assignment of the N-terminal GTPase domain of human Miro2 Bound to GTP. Biomolecular NMR assignments 0 36050579

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