Affinage

GEMIN7

Gem-associated protein 7 · UniProt Q9H840

Length
131 aa
Mass
14.5 kDa
Annotated
2026-06-10
15 papers in source corpus 12 papers cited in narrative 11 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/7 claims corpus-supported (86%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

GEMIN7 is a core structural subunit of the SMN complex, the cytoplasmic machinery that assembles spliceosomal snRNPs (PMID:12065586, PMID:17178713). It binds SMN directly through its arginine-glycine (RG) repeats and recruits Gemin6 into the complex, while also contacting Sm proteins, particularly SmE (PMID:12065586). Crystallographic analysis shows GEMIN7 adopts a canonical Sm fold despite lacking Sm sequence similarity and forms a heterodimer with Gemin6 through an Sm-protein-like interface (PMID:15939020). Together with SMN and Gemin8, GEMIN7 constitutes the central architectural building block onto which the rest of the complex assembles, as demonstrated by in vitro reconstitution from individual components (PMID:17178713); Gemin8 bridges SMN to the Gemin6/Gemin7 heterodimer, and its loss strips Gemin6, GEMIN7, and Unrip from SMN and impairs snRNP assembly (PMID:17023415, PMID:16434402). GEMIN7 additionally recruits Unrip via a stable direct interaction that is linked to cytoplasmic retention of the complex (PMID:16159890, PMID:15848170), and Gemin6/Gemin7/Unrip exist as a stable SMN-independent cytoplasmic subcomplex (PMID:17640873). Functionally, the Gemin6–Gemin7 heterodimer acts as a transient surrogate for the SmD3–SmB particle during snRNP formation and is exchanged out for the authentic Sm proteins in an Unrip-dependent step (PMID:19321448). This module architecture and its recruitment via Gemin8 are conserved in Drosophila (PMID:28949413).

Mechanistic history

Synthesis pass · year-by-year structured walk · 8 steps
  1. 2002 High

    Established GEMIN7 as a bona fide SMN complex member and defined its direct binding partners, answering whether it is a peripheral or integral component.

    Evidence Co-IP, immunolocalization, direct pull-down and mass spectrometry identifying SMN (via RG repeats), Gemin6, and Sm protein (SmE) contacts

    PMID:12065586

    Open questions at the time
    • No structural basis for the interactions
    • Functional role in snRNP assembly not yet tested
  2. 2005 High

    Solved how GEMIN7 and Gemin6 dimerize, revealing they mimic Sm proteins structurally and explaining their ability to bind Sm proteins.

    Evidence X-ray crystallography of the Gemin6-Gemin7 heterodimer plus in vitro Sm-protein binding

    PMID:15939020

    Open questions at the time
    • Did not establish whether the Sm-like fold serves a surrogate function in assembly
    • No structure within the full SMN complex
  3. 2005 High

    Identified GEMIN7 as the recruiter of Unrip into the SMN complex and linked this interaction to subcellular localization control.

    Evidence Reciprocal co-IP, RNAi knockdown of Unrip, and immunofluorescence showing altered nuclear SMN accumulation

    PMID:15848170 PMID:16159890

    Open questions at the time
    • Mechanism of cytoplasmic retention not resolved
    • Direct contribution of GEMIN7 (vs Unrip) to localization untested
  4. 2006 High

    Placed GEMIN7 within the central architectural core of the SMN complex by reconstituting the complex from purified parts.

    Evidence In vivo/in vitro binding assays and full reconstitution from individual components

    PMID:17178713

    Open questions at the time
    • Did not define GEMIN7's catalytic or surrogate role in assembly
    • Stoichiometry within reconstituted complex not detailed
  5. 2006 High

    Defined the Gemin8-dependent route by which the Gemin6/Gemin7/Unrip module joins SMN and showed this matters for snRNP assembly.

    Evidence RNAi of Gemin8, co-IP, and in vitro snRNP assembly assay showing reduced Sm protein (not snRNA) association upon disruption

    PMID:16434402 PMID:17023415

    Open questions at the time
    • Did not isolate GEMIN7's specific contribution from the module
    • Step in assembly affected not pinpointed
  6. 2007 Medium

    Demonstrated that the Gemin6/Gemin7/Unrip subcomplex is structurally autonomous from SMN, establishing it as a pre-formed module.

    Evidence Sedimentation analysis and immunoprecipitation showing persistence of the subcomplex upon SMN reduction

    PMID:17640873

    Open questions at the time
    • Single-lab sedimentation evidence
    • Functional purpose of the autonomous subcomplex untested
  7. 2009 Medium

    Revealed the mechanistic role of GEMIN7 as a transient Sm-protein surrogate that is displaced during snRNP maturation, clarifying why it adopts an Sm fold.

    Evidence Mammalian two-hybrid (Gemin2 interaction), in vitro stability/exchange assays, RNAi knockdown reducing assembly and SmE levels, and in vitro snRNP assembly showing Unrip-dependent exchange of the Gemin6-Gemin7 heterodimer for the SmD3-SmB particle

    PMID:19321448

    Open questions at the time
    • Single-lab in vitro reconstitution
    • Structural snapshot of the exchange step lacking
    • Trigger and timing of Unrip-dependent displacement unresolved
  8. 2017 Medium

    Showed evolutionary conservation of the Gemin6/7/Unrip module recruitment via Gemin8, generalizing the human assembly mechanism.

    Evidence In vivo interaction assays in Drosophila with Gemin6/Gemin7/Unrip homologues

    PMID:28949413

    Open questions at the time
    • Did not test functional consequences in the organism
    • Surrogate-exchange role not examined in Drosophila

Open questions

Synthesis pass · forward-looking unresolved questions
  • How GEMIN7's neuronal/axonal granule localization relates to its snRNP-assembly role, and whether it has SMN-complex-independent functions, remains unresolved.
  • Neurite granule localization (idx 8, 9) rests on imaging without functional manipulation of GEMIN7
  • No structure of GEMIN7 within the full assembling complex
  • Direct trigger of the Unrip-dependent surrogate exchange unknown

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:0005829 cytosol 2
Pathway
R-HSA-8953854 Metabolism of RNA 3
Partners
GEMIN2GEMIN6GEMIN8SMBSMD3SMESMNUNRIP
Complex memberships
Gemin6-Gemin7-Unrip subcomplexSMN complex

Evidence

Reading pass · 11 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2002 Gemin7 was identified as a novel component of the SMN complex. Direct binding experiments showed Gemin7 interacts directly with SMN via arginine-glycine (RG) repeats in Gemin7, and directly with Gemin6, mediating the association of Gemin6 with the SMN complex. Gemin7 also interacts with several Sm proteins, particularly SmE. Co-immunoprecipitation, immunolocalization, direct binding/pull-down experiments, mass spectrometry peptide sequencing The Journal of biological chemistry High 12065586
2005 Crystal structure of the Gemin6-Gemin7 heterodimer revealed that both proteins adopt canonical Sm folds despite no significant sequence similarity to Sm proteins, and they interact with each other via an interface similar to Sm protein-Sm protein interactions. The Gemin6/Gemin7 complex also binds to Sm proteins in vitro. X-ray crystallography, in vitro binding experiments Structure (London, England : 1993) High 15939020
2005 Unrip is recruited to the SMN complex via a stable direct interaction with Gemin7. This interaction is mutually exclusive with the unrip-unr complex. RNAi reduction of unrip leads to enhanced nuclear accumulation of SMN (increased gems/Cajal bodies), implicating unrip-Gemin7 interaction in cytoplasmic retention of the SMN complex. Co-immunoprecipitation, RNAi knockdown, immunofluorescence microscopy Human molecular genetics High 15848170 16159890
2005 Unrip interacts directly with Gemin6 and Gemin7 within the SMN complex, and unrip-containing SMN complexes are necessary and sufficient to mediate spliceosomal snRNP assembly in vitro. Co-immunoprecipitation, in vitro snRNP assembly assay FEBS letters Medium 15848170
2006 A comprehensive interaction map of the SMN complex showed that SMN, Gemin8, and Gemin7 form the central building block of the complex, onto which other components are assembled via multiple interactions. The SMN complex was reconstituted from individual components in vitro, confirming the central role of Gemin7. In vivo and in vitro binding assays, reconstitution of SMN complex from individual components The Journal of biological chemistry High 17178713
2006 Gemin6, Gemin7, and Unrip form a stable cytoplasmic subcomplex. Gemin8 binds directly to SMN and mediates the interaction of SMN with the Gemin6/Gemin7 heterodimer. Knockdown of Gemin8 disrupts the association of Gemin6, Gemin7, and Unrip with SMN, impairing snRNP assembly by reducing SMN complex association with Sm proteins but not snRNAs. RNA interference, co-immunoprecipitation, in vitro snRNP assembly assay, monoclonal antibody characterization The Journal of biological chemistry High 16434402 17023415
2007 Gemin6, Gemin7, and Unrip form a stable SMN-independent subcomplex (sedimentation experiments reveal a distinct Gemin6-Gemin7-unrip complex). This subunit persists at similar levels when SMN is reduced, indicating structural autonomy from SMN. Sedimentation analysis, immunoprecipitation of cell extracts The Journal of biological chemistry Medium 17640873
2009 A Gemin2-Gemin7 interaction was identified, and the SMN-Gemin7 interaction is stabilized in the presence of Gemin2. Gemin7 knockdown decreased snRNP assembly activity and reduced SmE protein in the SMN complex. Unrip, but not Gemin8, can remove Gemin7 from the stable SMN-Gemin2-Gemin7 ternary complex. In an in vitro snRNP assembly assay, the Gemin6-Gemin7 heterodimer is exchanged by the SmD3-SmB particle during snRNP formation, and this exchange requires Unrip. Mammalian two-hybrid assay, in vitro stability assay, RNAi knockdown, in vitro snRNP assembly assay The Journal of biological chemistry Medium 19321448
2005 Gemin7 was detected in neurite-like cytoplasmic extensions and growth cones of differentiating rat PC12 cells, as part of SMN complexes, consistent with a role in axonal transport of mRNPs. Immunofluorescence co-localization in differentiating PC12 cells Experimental cell research Low 15975577
2010 Live cell imaging of GFP-Gemin7 in neuronal cells showed that Gemin7 localizes to two distinct subsets of neurite granules: stationary bodies and smaller dynamic transport bodies, indicating Gemin7-containing SMN sub-complexes are present in axonal transport granules. Live cell imaging of GFP-tagged Gemin7 in neurite granules Biochemical and biophysical research communications Low 20188701
2017 In Drosophila, a Gemin6/7/Unrip module (with homologues of human Gemin6 and Gemin7) can be recruited to the SMN complex via the SMN-associated Gemin8 orthologue, mirroring the human SMN complex architecture. In vivo interaction assays in Drosophila FEBS letters Medium 28949413

Source papers

Stage 0 corpus · 15 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2006 A comprehensive interaction map of the human survival of motor neuron (SMN) complex. The Journal of biological chemistry 120 17178713
2005 A role for complexes of survival of motor neurons (SMN) protein with gemins and profilin in neurite-like cytoplasmic extensions of cultured nerve cells. Experimental cell research 111 15975577
2002 Identification and characterization of Gemin7, a novel component of the survival of motor neuron complex. The Journal of biological chemistry 92 12065586
2006 Gemin8 is a novel component of the survival motor neuron complex and functions in small nuclear ribonucleoprotein assembly. The Journal of biological chemistry 87 16434402
2005 Unrip, a factor implicated in cap-independent translation, associates with the cytosolic SMN complex and influences its intracellular localization. Human molecular genetics 70 16159890
2005 Unrip is a component of SMN complexes active in snRNP assembly. FEBS letters 66 15848170
2007 SMN-independent subunits of the SMN complex. Identification of a small nuclear ribonucleoprotein assembly intermediate. The Journal of biological chemistry 55 17640873
2006 Gemin8 is required for the architecture and function of the survival motor neuron complex. The Journal of biological chemistry 49 17023415
2005 The Gemin6-Gemin7 heterodimer from the survival of motor neurons complex has an Sm protein-like structure. Structure (London, England : 1993) 43 15939020
2003 The contribution of genetic and epigenetic mechanisms to gene silencing in oligodendrogliomas. Cancer research 36 14633674
2010 Analysis of SMN-neurite granules: Core Cajal body components are absent from SMN-cytoplasmic complexes. Biochemical and biophysical research communications 24 20515655
2009 Role of survival motor neuron complex components in small nuclear ribonucleoprotein assembly. The Journal of biological chemistry 21 19321448
2010 SMN and the Gemin proteins form sub-complexes that localise to both stationary and dynamic neurite granules. Biochemical and biophysical research communications 20 20188701
2017 Novel interactors of the Drosophila Survival Motor Neuron (SMN) Complex suggest its full conservation. FEBS letters 17 28949413
2018 Sporadic amyotrophic lateral sclerosis: is SMN-Gemins protein complex of importance for the relative resistance of oculomotor nucleus motoneurons to degeneration? Folia neuropathologica 0 30786668

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