GMFG encodes glia maturation factor gamma, an ADF-H/cofilin-like GMF-family actin regulator that binds the Arp2/3 complex and remodels branched actin networks. The strongest current evidence supports Arp2/3 binding, inhibition of Arp2/3-mediated nucleation, and actin filament debranching at cortical and immune-cell actin structures, with downstream roles in leukocyte migration, integrin trafficking, immune synapse remodeling, and BCR signaling.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
|
GO:0071933
Arp2/3 complex binding
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: This IBA annotation captures the best-supported molecular function of GMFG as an Arp2/3 complex-binding GMF-family actin network remodeling factor.
Reason: Falcon research, InterPro/UniProt domain context, and phylogenetic annotation converge on GMFG functioning through Arp2/3 binding rather than as a generic glial growth factor.
Supporting Evidence:
file:human/GMFG/GMFG-deep-research-falcon.md
GMFG is an ADF-H family protein that binds the Arp2/3 complex rather than actin itself; it inhibits Arp2/3-dependent nucleation and catalyzes debranching/pruning of daughter filaments at branch junctions.
|
|
GO:0030864
cortical actin cytoskeleton
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: Cortical actin cytoskeleton is an appropriate active site for GMFG's Arp2/3-dependent branched actin remodeling function.
Reason: GMFG is discussed as cytosolic and enriched at actin remodeling sites such as leading edges, immune synapses, and focal adhesions; cortical actin cytoskeleton is the most specific existing GOA location.
Supporting Evidence:
file:human/GMFG/GMFG-deep-research-falcon.md
Across experimental contexts, GMFgamma is primarily discussed as a cytosolic protein enriched at actin remodeling sites
|
|
GO:0071846
actin filament debranching
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: Actin filament debranching is a core biological process for GMFG/GMF family proteins acting on Arp2/3-branched actin networks.
Reason: This term is specific and mechanistically aligned with GMFG's conserved Arp2/3-regulatory activity.
Supporting Evidence:
file:human/GMFG/GMFG-deep-research-falcon.md
Debranching: removal/dissociation of the daughter filament at an Arp2/3-mediated branch junction, which contributes to turnover of branched actin arrays and recycling of Arp2/3.
|
|
GO:0034316
negative regulation of Arp2/3 complex-mediated actin nucleation
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: This annotation captures the inhibitory arm of GMFG function toward Arp2/3-mediated nucleation.
Reason: The term is mechanistically specific and complements the debranching annotation; both are part of GMF-family remodeling of branched actin arrays.
Supporting Evidence:
file:human/GMFG/GMFG-deep-research-falcon.md
A central concept is that branched actin networks (e.g., lamellipodia) are nucleated by Arp2/3 complex, and GMF proteins can both (i) inhibit Arp2/3-mediated nucleation and (ii) catalyze debranching/pruning
|
|
GO:0007165
signal transduction
|
IEA
GO_REF:0000108 |
MARK AS OVER ANNOTATED |
Summary: This broad IEA appears to derive from the legacy "growth factor" view of GMF proteins rather than from GMFG's current mechanistic annotation.
Reason: GMFG can affect immune signaling through actin remodeling, but signal transduction is too broad and indirect for the protein's core molecular role.
Supporting Evidence:
file:human/GMFG/GMFG-deep-research-falcon.md
Human GMFG (GMFgamma) is an ADF-H/cofilin-like Arp2/3-binding regulator that remodels branched actin networks
|
|
GO:0003779
actin binding
|
IEA
GO_REF:0000002 |
MODIFY |
Summary: The ADF-H domain supports a relationship to actin-network regulation, but Falcon research indicates that the more precise molecular target for GMFG is the Arp2/3 complex rather than generic actin binding.
Reason: Replace this generic term with the more informative Arp2/3 complex binding term, which is already present in GOA and better describes GMFG's core molecular function.
Proposed replacements:
Arp2/3 complex binding
Supporting Evidence:
file:human/GMFG/GMFG-deep-research-falcon.md
GMFG is an ADF-H family protein that binds the Arp2/3 complex rather than actin itself
|
|
GO:0008083
growth factor activity
|
IEA
GO_REF:0000043 |
REMOVE |
Summary: The growth factor activity annotation reflects the historical protein name rather than current mechanistic evidence for human GMFG.
Reason: GMFG lacks evidence for secreted growth factor molecular activity in the current review context; its supported role is intracellular Arp2/3 and actin-network remodeling.
Supporting Evidence:
file:human/GMFG/GMFG-deep-research-falcon.md
GMFG is best positioned as a mechanistic node and candidate biomarker rather than a validated therapeutic target.
|
|
GO:0071846
actin filament debranching
|
IEA
GO_REF:0000002 |
ACCEPT |
Summary: The InterPro2GO IEA agrees with the IBA annotation and with the GMF-family mechanistic literature.
Reason: Actin filament debranching is a specific, core biological process for GMFG and is supported by family/domain evidence.
Supporting Evidence:
file:human/GMFG/GMFG-deep-research-falcon.md
Human GMFG (GMFgamma) is an ADF-H/cofilin-like Arp2/3-binding regulator that remodels branched actin networks by inhibiting Arp2/3-dependent nucleation and catalyzing debranching
|
|
GO:0071933
Arp2/3 complex binding
|
IEA
GO_REF:0000002 |
ACCEPT |
Summary: The InterPro2GO Arp2/3 complex binding annotation is consistent with the stronger IBA annotation and the falcon-summarized literature.
Reason: This is the most informative molecular-function annotation currently in GMFG GOA.
Supporting Evidence:
file:human/GMFG/GMFG-deep-research-falcon.md
Biochemical and structural work summarized in an authoritative review indicates that GMF binds the Arp2/3 complex at two sites
|
|
GO:0005576
extracellular region
|
TAS
Reactome:R-HSA-6798748 |
KEEP AS NON CORE |
Summary: Reactome links GMFG to neutrophil degranulation/exocytosis datasets, where proteins can be released or detected extracellularly.
Reason: This may reflect immune-cell granule/exocytosis context, but the core functional location for GMFG is intracellular actin-remodeling sites.
Supporting Evidence:
file:human/GMFG/GMFG-uniprot.txt
Reactome; R-HSA-6798695; Neutrophil degranulation.
|
|
GO:0005576
extracellular region
|
TAS
Reactome:R-HSA-6800434 |
KEEP AS NON CORE |
Summary: Duplicate Reactome extracellular-region annotation from ficolin-rich granule exocytosis context.
Reason: Retain as non-core Reactome localization evidence; it should not displace the intracellular cortical actin cytoskeleton as the functional site.
Supporting Evidence:
file:human/GMFG/GMFG-uniprot.txt
Reactome; R-HSA-6798695; Neutrophil degranulation.
|
|
GO:0034774
secretory granule lumen
|
TAS
Reactome:R-HSA-6798748 |
KEEP AS NON CORE |
Summary: This Reactome location may reflect detection in neutrophil granule contents rather than the site of GMFG's actin-remodeling activity.
Reason: GMFG is relevant to immune cells, but its core function remains intracellular Arp2/3/actin network regulation.
Supporting Evidence:
file:human/GMFG/GMFG-uniprot.txt
Reactome; R-HSA-6798695; Neutrophil degranulation.
|
|
GO:1904813
ficolin-1-rich granule lumen
|
TAS
Reactome:R-HSA-6800434 |
KEEP AS NON CORE |
Summary: Ficolin-1-rich granule lumen is plausible as Reactome immune-cell context but is not the primary functional site for GMFG.
Reason: Retain as non-core granule-context annotation while emphasizing cortical actin cytoskeleton and cytosolic actin-remodeling locations as core.
Supporting Evidence:
file:human/GMFG/GMFG-uniprot.txt
Reactome; R-HSA-6798695; Neutrophil degranulation.
|
|
GO:0004860
protein kinase inhibitor activity
|
TAS
PMID:8639570 In vitro inhibition of MAP kinase (ERK1/ERK2) activity by ph... |
REMOVE |
Summary: The cited study tested phosphorylated GMF as an in vitro ERK inhibitor, but it predates GMFG-specific isolation and does not establish this as a human GMFG molecular function.
Reason: This annotation is not transferable to GMFG: the cited in vitro work used recombinant GMF described as a brain protein, consistent with the brain-expressed GMFB isoform rather than immune-cell-expressed GMFG. Current GMFG evidence supports Arp2/3/actin-network remodeling instead.
Supporting Evidence:
PMID:8639570
recombinant glia maturation factor (GMF), a 17-kDa brain protein, inhibits the activity of mitogen-activated protein (MAP) kinase in the test tube assay
|
|
GO:0006468
protein phosphorylation
|
TAS
PMID:7598724 Phorbol ester stimulates rapid intracellular phosphorylation... |
REMOVE |
Summary: This is a substrate/process misannotation: the cited paper describes GMF being phosphorylated by kinases, not GMFG catalyzing protein phosphorylation.
Reason: GMFG is not a kinase. The cited evidence supports post-translational regulation of GMF proteins, not assignment of the phosphorylation biological process to GMFG as an actor.
Supporting Evidence:
PMID:7598724
recombinant glia maturation factor (GMF), a 17-kD brain protein, can be phosphorylated in vitro at the serine residue by protein kinase C (PKC), protein kinase A (PKA), and casein kinase II (CKII)
|
|
GO:0008047
enzyme activator activity
|
TAS
PMID:8798479 In vitro enhancement of p38 mitogen-activated protein kinase... |
REMOVE |
Summary: The cited work reports in vitro activation of p38 MAP kinase by phosphorylated GMF, but does not support enzyme activator activity as a current core function for GMFG.
Reason: This legacy activity is not transferable to GMFG: the cited phosphorylated-GMF experiments reflect brain-derived/brain-expressed GMF biology, which is most consistent with GMFB rather than immune-cell-expressed GMFG. Current GMFG evidence supports Arp2/3-dependent actin network remodeling.
Supporting Evidence:
PMID:8798479
PKA-phosphorylated GMF strongly enhances the activity of a related but distinct subfamily of MAP kinase, the p38 MAP kinase
|
Q: Which human immune-cell contexts require GMFG's Arp2/3 debranching activity directly, rather than indirect effects on integrin trafficking?
Q: Are the Reactome granule/extracellular annotations true GMFG localization states or proteomics carryover from neutrophil degranulation datasets?
Q: Do historical MAPK inhibitor/activator findings apply to GMFG specifically, or only to GMFB/undifferentiated GMF preparations?
Experiment: Endogenous GMFG tagging in primary monocytes and B cells followed by live imaging of Arp2/3, F-actin, and integrin recycling during chemotaxis or immune synapse formation.
Hypothesis: GMFG localizes to cortical actin remodeling sites where Arp2/3-dependent debranching supports immune-cell migration and synapse dynamics.
Type: live-cell imaging/genome editing
Experiment: Biochemical reconstitution comparing purified human GMFG and GMFB for Arp2/3 binding, nucleation inhibition, and branch deassembly using TIRF microscopy.
Hypothesis: GMFG has direct Arp2/3-regulatory activity comparable to other GMF-family proteins and does not require legacy MAPK-modulatory activity to explain its core function.
Type: biochemical reconstitution
Experiment: Proteomic reanalysis of neutrophil granule/extracellular fractions with endogenous GMFG controls and cytosolic contamination markers.
Hypothesis: Reactome granule/extracellular annotations reflect immune-cell degranulation datasets rather than the primary functional location of GMFG.
Type: proteomics/localization validation
The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.
We are interested in where in or outside the cell the gene product carries out its function.
We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
The evidence reviewed consistently refers to GMFG (glia maturation factor γ; GMFγ) as a human ADF-H (actin depolymerizing factor homology) family/cofilin-like protein that binds the Arp2/3 complex and regulates branched actin network remodeling—matching the UniProt O60234 description and domain/family context provided (ADF-H/Cofilin-like; GMF family). (goode2018gmfasan pages 11-11, goode2018gmfasan pages 1-2)
GMFγ/GMFG is best understood as an Arp2/3-regulatory actin network remodeling factor rather than an actin monomer/filament binding factor. A central concept is that branched actin networks (e.g., lamellipodia) are nucleated by Arp2/3 complex, and GMF proteins can both (i) inhibit Arp2/3-mediated nucleation and (ii) catalyze debranching/pruning of daughter filaments from branch junctions, thereby promoting turnover and remodeling of branched networks. (goode2018gmfasan pages 3-6, goode2018gmfasan pages 1-2)
Biochemical and structural work summarized in an authoritative review indicates that GMF binds the Arp2/3 complex at two sites, with reported binding affinities (Kd ~10 nM and ~1 mM for high-/low-affinity sites), and directly contacts Arp2 and p40/ARPC1 (with additional interaction proposed involving Arp3). (goode2018gmfasan pages 3-6)
A key mechanistic definition:
- Debranching: removal/dissociation of the daughter filament at an Arp2/3-mediated branch junction, which contributes to turnover of branched actin arrays and recycling of Arp2/3. (goode2018gmfasan pages 3-6, goode2018gmfasan pages 6-7)
GMFγ/GMF is reported to preferentially bind an ADP-Arp2/3 state (relative to ATP-Arp2/3), consistent with acting on “older” branches (where nucleotide hydrolysis has progressed). This provides a conceptual framework for why GMF-mediated pruning can selectively remodel existing networks while modulating new branch formation. (goode2018gmfasan pages 7-9, goode2018gmfasan pages 6-7)
Branched actin networks at the leading edge (lamellipodia) underlie cell protrusion and directed migration. GMF proteins are described as being enriched in retracting/mature lamellipodia and promoting leading-edge remodeling (including retraction/ruffling), consistent with a role in coordinating protrusive versus retractile behavior during migration. (goode2018gmfasan pages 3-6, goode2018gmfasan pages 6-7)
A primary experimental study in human monocytes supports a role for GMFG in chemotaxis and adhesion via β1-integrin (α5β1) stability and recycling.
Key findings (Aerbajinai et al., J Biol Chem, Apr 2016, https://doi.org/10.1074/jbc.m115.674200):
- GMFG knockdown impaired chemotactic migration toward fMLP and SDF-1α (CXCL12) and reduced α5β1-integrin-mediated adhesion. (aerbajinai2016gliamaturationfactorγ pages 1-2)
- Mechanistically, GMFG regulated β1-integrin ubiquitination, reduced β1-integrin degradation, and promoted recycling of internalized integrin back to the plasma membrane.
- GMFG interacted with syntaxin 4 (STX4) and STXBP4, and STXBP4 knockdown reduced migration and β1-integrin surface expression, consistent with a trafficking mechanism. (aerbajinai2016gliamaturationfactorγ pages 1-2)
This places GMFG at the intersection of Arp2/3-dependent actin remodeling and vesicular trafficking pathways that control integrin turnover during directed migration. (aerbajinai2016gliamaturationfactorγ pages 1-2)
A mechanistic study in human B cell lines demonstrates that GMFγ supports immune synapse actin dynamics and antigen-dependent signaling.
Deretic et al., Frontiers in Cell and Developmental Biology, Jul 2021, https://doi.org/10.3389/fcell.2021.647063:
- siRNA-mediated depletion of GMFγ reduced actin retrograde flow velocity (analysis of 52 tracks from 9 control cells vs 51 tracks from 11 GMFγ-depleted cells; p<0.0001). (deretic2021theactindisassemblyprotein pages 8-10)
- GMFγ depletion impaired coalescence of BCR microclusters into a central cluster (cSMAC): approximately ~60% of control cells formed a cSMAC after 30 min vs ~40% of GMFγ-depleted cells. (deretic2021theactindisassemblyprotein pages 8-10)
- GMFγ localized just inside the peripheral F-actin ring at the immune synapse, consistent with a spatially organized role in actin remodeling at the contact site. (deretic2021theactindisassemblyprotein pages 6-7)
The authors interpret the similarity between GMFγ depletion phenotypes and Arp2/3 inhibition as evidence that GMFγ can cooperate with Arp2/3-mediated actin remodeling to support antigen-dependent BCR signaling amplification. (deretic2021theactindisassemblyprotein pages 1-2, deretic2021theactindisassemblyprotein pages 8-10)
Gerlach et al., American Journal of Respiratory Cell and Molecular Biology, Aug 2019, https://doi.org/10.1165/rcmb.2018-0352oc, provides evidence that phosphorylation of GMFγ at Y104 coordinates lamellipodial and focal adhesion behavior in human airway smooth muscle cells.
Quantitative imaging outputs reported include vinculin surface counts and GMFγ spot counts across GMFγ variants:
- Vinculin surface counts: WT 1,119; Y104F 1,801; Y104D 1,827 (n=10 cells; comparisons reported with P<0.05 in the described analysis). (gerlach2019phosphorylationofgmfγ pages 9-10)
- GMFγ spot counts: WT 14,916; Y104F 14,475; Y104D 10,723* (n=10 cells). (gerlach2019phosphorylationofgmfγ pages 9-10)
This supports a model in which GMFγ phosphorylation state and actomyosin activity influence its recruitment to adhesion structures and thereby alter migration-related dynamics. (gerlach2019phosphorylationofgmfγ pages 9-10)
An expert review frames phosphorylation as a key mode of GMF regulation that can alter Arp2/3 binding and debranching activity, integrating small GTPase signaling with actin network remodeling outcomes. (goode2018gmfasan pages 7-9)
Across experimental contexts, GMFγ is primarily discussed as a cytosolic protein enriched at actin remodeling sites:
- Leading edge / lamellipodia in migrating cells (consistent with remodeling branched actin arrays). (goode2018gmfasan pages 3-6, goode2018gmfasan pages 6-7)
- Endosomal compartments in macrophages (early/late endosomes) in connection with receptor trafficking (review synthesis). (goode2018gmfasan pages 6-7)
- Immune synapse: endogenous GMFγ localized adjacent to the interior face of the peripheral F-actin ring. (deretic2021theactindisassemblyprotein pages 6-7)
- Focal adhesions: recruitment influenced by myosin activity and GMFγ phosphorylation state (Y104). (gerlach2019phosphorylationofgmfγ pages 9-10)
Li et al., Stem Cell Research & Therapy, Apr 2023, https://doi.org/10.1186/s13287-023-03328-1, reports that gmfg is required for initiation and maintenance of embryonic hematopoietic stem and progenitor cells (HSPCs) in zebrafish embryos, with complementary assays in HUVECs.
Key mechanistic conclusions:
- gmfg loss reduced hemogenic endothelium and HSPCs, with downstream reductions in multiple blood lineages.
- gmfg deficiency suppressed YAP activity by preventing YAP nuclear translocation and contributed to Notch inactivation; induction of Notch intracellular domain partially rescued defects. (li2023gliamaturationfactorγ pages 1-2)
Interpretation: while not human in vivo genetics, this study is a recent mechanistic advance connecting gmfg to flow-responsive developmental hematopoiesis via the YAP/Notch axis. (li2023gliamaturationfactorγ pages 1-2)
Search results identified multiple 2023–2024 papers in which GMFG appears in computational signatures (e.g., cancer prognostic models, sepsis classifiers), but the accessible full-text chunks in this run did not provide extractable quantitative model performance (e.g., HRs for GMFG specifically, or per-gene effect sizes) beyond what is in the mechanistic sources above. Therefore, this report does not assert additional 2023–2024 clinical statistics without direct evidentiary support from retrieved texts. (li2023gliamaturationfactorγ pages 18-19)
Based on the experimentally supported roles above, GMFG is most directly relevant in applications where Arp2/3-mediated actin remodeling and immune cell behavior are central:
- Immune cell chemotaxis/extravasation and inflammatory trafficking, via integrin recycling and actin remodeling mechanisms. (aerbajinai2016gliamaturationfactorγ pages 1-2)
- Adaptive immune synapse function, where actin retrograde flow and receptor microcluster centralization influence signal amplification. (deretic2021theactindisassemblyprotein pages 8-10)
Within the evidence available here, GMFG is best positioned as a mechanistic node and candidate biomarker rather than a validated therapeutic target. The strongest “real-world” readouts in the provided evidence are quantitative cell biological phenotypes (migration/spreading/flow) rather than validated clinical endpoints. (aerbajinai2016gliamaturationfactorγ pages 1-2, deretic2021theactindisassemblyprotein pages 8-10)
A key authoritative synthesis is the Trends in Cell Biology (2018) review (Goode et al., Sep 2018, https://doi.org/10.1016/j.tcb.2018.04.008), which frames GMF proteins (including human GMFγ/GMFG) as actin network remodeling factors that bind Arp2/3, inhibit nucleation, and catalyze debranching, integrating biochemical mechanisms with cell migration phenotypes and outlining phosphorylation as a regulatory principle. (goode2018gmfasan pages 3-6, goode2018gmfasan pages 7-9)
The following table consolidates the most important functional-annotation points, with publication dates and URLs.
| Aspect | Functional annotation for human GMFG (UniProt O60234) | Key supporting paper(s) | Year | Journal | URL | Quantitative data points | Citation |
|---|---|---|---|---|---|---|---|
| Molecular function: Arp2/3 binding and actin branch remodeling | GMFG is an ADF-H family protein that binds the Arp2/3 complex rather than actin itself; it inhibits Arp2/3-dependent nucleation and catalyzes debranching/pruning of daughter filaments at branch junctions. Direct contacts with Arp2 and p40/ARPC1 are reported, with a proposed secondary interaction involving Arp3. | Goode et al., GMF as an Actin Network Remodeling Factor | 2018 | Trends in Cell Biology | https://doi.org/10.1016/j.tcb.2018.04.008 | Reported Arp2/3 binding sites with Kd values of 10 nM and 1 mM | (goode2018gmfasan pages 3-6, goode2018gmfasan pages 1-2) |
| Mechanistic specificity | GMFG preferentially binds ADP-Arp2/3 over ATP-Arp2/3, consistent with targeting older branched networks; it may catalyze Pi release from Arp2/3 and keep GMF-bound Arp2/3 nucleation-incompetent until dissociation. | Goode et al., GMF as an Actin Network Remodeling Factor | 2018 | Trends in Cell Biology | https://doi.org/10.1016/j.tcb.2018.04.008 | Preference for ADP-Arp2/3 noted; no exact numeric ratio in snippet | (goode2018gmfasan pages 7-9, goode2018gmfasan pages 6-7) |
| Cell migration / lamellipodia | GMFG promotes remodeling of branched lamellipodial actin networks, supports retraction/ruffling, and is important for directed migration. In migrating cells, GMF family proteins are enriched in retracting or mature lamellipodia and help convert branched arrays into more parallel arc-like structures. | Goode et al., GMF as an Actin Network Remodeling Factor | 2018 | Trends in Cell Biology | https://doi.org/10.1016/j.tcb.2018.04.008 | Debranching activity identified as critical for leading-edge dynamics; no single numeric effect size in snippet | (goode2018gmfasan pages 3-6, goode2018gmfasan pages 6-7) |
| Monocyte chemotaxis / integrin trafficking | In human monocytes, GMFG regulates chemotaxis and adhesion by maintaining α5β1/β1-integrin stability, preventing proteasomal degradation, and promoting recycling back to the plasma membrane. It also interacts with STX4 and STXBP4, with STXBP4 functionally important for migration and β1-integrin recycling. | Aerbajinai et al., Glia Maturation Factor-γ Regulates Monocyte Migration through Modulation of β1-Integrin | 2016 | Journal of Biological Chemistry | https://doi.org/10.1074/jbc.m115.674200 | GMFG knockdown impaired chemotaxis toward fMLP and SDF-1α; exact values not provided in snippet | (aerbajinai2016gliamaturationfactorγ pages 13-14, aerbajinai2016gliamaturationfactorγ pages 1-2) |
| Immune-cell context / expression | GMFG is preferentially expressed in inflammatory cells and microvascular endothelial cells, consistent with roles in immune-cell migration, extravasation, and inflammatory responses. It has been implicated in neutrophil and T-cell chemotaxis in addition to monocyte migration. | Aerbajinai et al.; Goode et al. | 2016; 2018 | JBC; Trends in Cell Biology | https://doi.org/10.1074/jbc.m115.674200; https://doi.org/10.1016/j.tcb.2018.04.008 | Expression preference described qualitatively; no numeric tissue-expression values in snippet | (goode2018gmfasan pages 11-11, aerbajinai2016gliamaturationfactorγ pages 13-14, aerbajinai2016gliamaturationfactorγ pages 1-2) |
| Subcellular localization | GMFG is cytosolic and associated with the leading edge/lamellipodia in migrating cells. Additional evidence places GMFG on early and late endosomes in macrophages, linking it to receptor trafficking and endocytic processes. In B cells, endogenous GMFγ localizes just interior to the peripheral F-actin ring at the immune synapse. | Goode et al.; Deretic et al. | 2018; 2021 | Trends in Cell Biology; Frontiers in Cell and Developmental Biology | https://doi.org/10.1016/j.tcb.2018.04.008; https://doi.org/10.3389/fcell.2021.647063 | In B cells, localization peak is closer to cell center than the actin peak; no exact distance given in snippet | (goode2018gmfasan pages 6-7, goode2018gmfasan pages 1-2, deretic2021theactindisassemblyprotein pages 6-7) |
| Immune synapse / BCR signaling | GMFγ enhances actin remodeling at the B-cell immune synapse, supporting spreading on antigen-coated surfaces, actin retrograde flow, BCR microcluster coalescence, and APC-induced BCR signaling. The depletion phenotype resembles Arp2/3 inhibition, supporting a cooperative role with Arp2/3 in signal amplification. | Deretic et al., The Actin-Disassembly Protein Glia Maturation Factor γ Enhances Actin Remodeling and B Cell Antigen Receptor Signaling at the Immune Synapse | 2021 | Frontiers in Cell and Developmental Biology | https://doi.org/10.3389/fcell.2021.647063 | Actin-flow analysis used 52 tracks/9 control cells vs 51 tracks/11 GMFγ-depleted cells; p < 0.0001 | (deretic2021theactindisassemblyprotein pages 1-2, deretic2021theactindisassemblyprotein pages 8-10) |
| B-cell spreading / cSMAC formation | GMFγ is needed for sustained spreading at later time points and efficient central supramolecular activation cluster formation. Early spreading is relatively preserved, but sustained contact expansion and microcluster centralization are impaired by GMFγ depletion. | Deretic et al. | 2021 | Frontiers in Cell and Developmental Biology | https://doi.org/10.3389/fcell.2021.647063 | ~60% of control cells vs ~40% of GMFγ-depleted cells formed a cSMAC after 30 min; BCR levels in Ramos cells 95 ± 6% of control | (deretic2021theactindisassemblyprotein pages 8-10, deretic2021theactindisassemblyprotein pages 6-7) |
| PTM regulation | Phosphorylation regulates GMFG function. c-Abl-dependent phosphorylation at Y104 coordinates the balance between lamellipodial dynamics and focal adhesion growth in human airway smooth muscle cells. More broadly, phosphoregulation can weaken Arp2/3 binding and modulate debranching activity. | Gerlach et al., Phosphorylation of GMFγ by c-Abl Coordinates Lamellipodial and Focal Adhesion Dynamics to Regulate Airway Smooth Muscle Cell Migration; Goode et al. | 2019; 2018 | American Journal of Respiratory Cell and Molecular Biology; Trends in Cell Biology | https://doi.org/10.1165/rcmb.2018-0352oc; https://doi.org/10.1016/j.tcb.2018.04.008 | Vinculin surface counts: WT 1,119; Y104F 1,801; Y104D 1,827 (n = 10 cells, P < 0.05 vs comparator in snippet) | (gerlach2019phosphorylationofgmfγ pages 9-10, goode2018gmfasan pages 7-9) |
| PTM-linked localization dynamics | Myosin activity influences GMFγ recruitment to focal adhesions, and Y104 phosphorylation state changes GMFγ distribution between leading edge and adhesions. | Gerlach et al. | 2019 | American Journal of Respiratory Cell and Molecular Biology | https://doi.org/10.1165/rcmb.2018-0352oc | GMFγ spot counts: WT 14,916; Y104F 14,475; Y104D 10,723 (n = 10 cells) | (gerlach2019phosphorylationofgmfγ pages 9-10) |
| Hematopoietic pathway relevance | Recent work supports a role for gmfg in initiation and maintenance of hematopoietic stem and progenitor cells, with blood-flow-responsive regulation and effects on YAP nuclear translocation and Notch signaling. This is strong pathway evidence but comes primarily from zebrafish/HUVEC systems rather than direct human in vivo genetics. | Li et al., Glia maturation factor-γ is required for initiation and maintenance of hematopoietic stem and progenitor cells | 2023 | Stem Cell Research & Therapy | https://doi.org/10.1186/s13287-023-03328-1 | Phenotype includes reduced hemogenic endothelium, HSPCs, erythrocytes, myelocytes, and lymphocytes; exact counts not provided in snippet | (li2023gliamaturationfactorγ pages 1-2) |
Table: This table summarizes experimentally supported functions, localization, regulatory mechanisms, and pathway roles for human GMFG/GMFγ, emphasizing Arp2/3-dependent actin remodeling and immune-cell biology. It also highlights recent mechanistic studies and includes quantitative values where those were explicitly available in the evidence snippets.
Human GMFG (GMFγ) is an ADF-H/cofilin-like Arp2/3-binding regulator that remodels branched actin networks by inhibiting Arp2/3-dependent nucleation and catalyzing debranching at actin branch junctions; this activity supports dynamic behaviors including directed leukocyte migration (via integrin trafficking) and immune synapse actin remodeling and BCR signal amplification, with regulation by phosphorylation (including c-Abl–linked Y104 phosphorylation) and localization at leading-edge, synapse-proximal actin structures, endosomal compartments, and focal adhesions. (goode2018gmfasan pages 3-6, aerbajinai2016gliamaturationfactorγ pages 1-2, deretic2021theactindisassemblyprotein pages 8-10, gerlach2019phosphorylationofgmfγ pages 9-10)
References
(goode2018gmfasan pages 11-11): Bruce L. Goode, Meredith O. Sweeney, and Julian A. Eskin. Gmf as an actin network remodeling factor. Trends in cell biology, 28 9:749-760, Sep 2018. URL: https://doi.org/10.1016/j.tcb.2018.04.008, doi:10.1016/j.tcb.2018.04.008. This article has 39 citations and is from a domain leading peer-reviewed journal.
(goode2018gmfasan pages 1-2): Bruce L. Goode, Meredith O. Sweeney, and Julian A. Eskin. Gmf as an actin network remodeling factor. Trends in cell biology, 28 9:749-760, Sep 2018. URL: https://doi.org/10.1016/j.tcb.2018.04.008, doi:10.1016/j.tcb.2018.04.008. This article has 39 citations and is from a domain leading peer-reviewed journal.
(goode2018gmfasan pages 3-6): Bruce L. Goode, Meredith O. Sweeney, and Julian A. Eskin. Gmf as an actin network remodeling factor. Trends in cell biology, 28 9:749-760, Sep 2018. URL: https://doi.org/10.1016/j.tcb.2018.04.008, doi:10.1016/j.tcb.2018.04.008. This article has 39 citations and is from a domain leading peer-reviewed journal.
(goode2018gmfasan pages 6-7): Bruce L. Goode, Meredith O. Sweeney, and Julian A. Eskin. Gmf as an actin network remodeling factor. Trends in cell biology, 28 9:749-760, Sep 2018. URL: https://doi.org/10.1016/j.tcb.2018.04.008, doi:10.1016/j.tcb.2018.04.008. This article has 39 citations and is from a domain leading peer-reviewed journal.
(goode2018gmfasan pages 7-9): Bruce L. Goode, Meredith O. Sweeney, and Julian A. Eskin. Gmf as an actin network remodeling factor. Trends in cell biology, 28 9:749-760, Sep 2018. URL: https://doi.org/10.1016/j.tcb.2018.04.008, doi:10.1016/j.tcb.2018.04.008. This article has 39 citations and is from a domain leading peer-reviewed journal.
(aerbajinai2016gliamaturationfactorγ pages 1-2): Wulin Aerbajinai, Lunhua Liu, Jianqiong Zhu, Chutima Kumkhaek, Kyung Chin, and Griffin P. Rodgers. Glia maturation factor-γ regulates monocyte migration through modulation of β1-integrin. Journal of Biological Chemistry, 291:8549-8564, Apr 2016. URL: https://doi.org/10.1074/jbc.m115.674200, doi:10.1074/jbc.m115.674200. This article has 36 citations and is from a domain leading peer-reviewed journal.
(deretic2021theactindisassemblyprotein pages 8-10): Nikola Deretic, Madison Bolger-Munro, Kate Choi, Libin Abraham, and Michael R. Gold. The actin-disassembly protein glia maturation factor γ enhances actin remodeling and b cell antigen receptor signaling at the immune synapse. Frontiers in Cell and Developmental Biology, Jul 2021. URL: https://doi.org/10.3389/fcell.2021.647063, doi:10.3389/fcell.2021.647063. This article has 4 citations.
(deretic2021theactindisassemblyprotein pages 6-7): Nikola Deretic, Madison Bolger-Munro, Kate Choi, Libin Abraham, and Michael R. Gold. The actin-disassembly protein glia maturation factor γ enhances actin remodeling and b cell antigen receptor signaling at the immune synapse. Frontiers in Cell and Developmental Biology, Jul 2021. URL: https://doi.org/10.3389/fcell.2021.647063, doi:10.3389/fcell.2021.647063. This article has 4 citations.
(deretic2021theactindisassemblyprotein pages 1-2): Nikola Deretic, Madison Bolger-Munro, Kate Choi, Libin Abraham, and Michael R. Gold. The actin-disassembly protein glia maturation factor γ enhances actin remodeling and b cell antigen receptor signaling at the immune synapse. Frontiers in Cell and Developmental Biology, Jul 2021. URL: https://doi.org/10.3389/fcell.2021.647063, doi:10.3389/fcell.2021.647063. This article has 4 citations.
(gerlach2019phosphorylationofgmfγ pages 9-10): Brennan D. Gerlach, Kate Tubbesing, Guoning Liao, Alyssa C. Rezey, Ruping Wang, Margarida Barroso, and Dale D. Tang. Phosphorylation of gmfγ by c-abl coordinates lamellipodial and focal adhesion dynamics to regulate airway smooth muscle cell migration. American journal of respiratory cell and molecular biology, 61:219-231, Aug 2019. URL: https://doi.org/10.1165/rcmb.2018-0352oc, doi:10.1165/rcmb.2018-0352oc. This article has 20 citations and is from a peer-reviewed journal.
(li2023gliamaturationfactorγ pages 1-2): Honghu Li, Qian Luo, Shuyang Cai, Ruxiu Tie, Ye Meng, Wei Shan, Yulin Xu, Xiangjun Zeng, Pengxu Qian, and He Huang. Glia maturation factor-γ is required for initiation and maintenance of hematopoietic stem and progenitor cells. Stem Cell Research & Therapy, Apr 2023. URL: https://doi.org/10.1186/s13287-023-03328-1, doi:10.1186/s13287-023-03328-1. This article has 0 citations and is from a peer-reviewed journal.
(li2023gliamaturationfactorγ pages 18-19): Honghu Li, Qian Luo, Shuyang Cai, Ruxiu Tie, Ye Meng, Wei Shan, Yulin Xu, Xiangjun Zeng, Pengxu Qian, and He Huang. Glia maturation factor-γ is required for initiation and maintenance of hematopoietic stem and progenitor cells. Stem Cell Research & Therapy, Apr 2023. URL: https://doi.org/10.1186/s13287-023-03328-1, doi:10.1186/s13287-023-03328-1. This article has 0 citations and is from a peer-reviewed journal.
(aerbajinai2016gliamaturationfactorγ pages 13-14): Wulin Aerbajinai, Lunhua Liu, Jianqiong Zhu, Chutima Kumkhaek, Kyung Chin, and Griffin P. Rodgers. Glia maturation factor-γ regulates monocyte migration through modulation of β1-integrin. Journal of Biological Chemistry, 291:8549-8564, Apr 2016. URL: https://doi.org/10.1074/jbc.m115.674200, doi:10.1074/jbc.m115.674200. This article has 36 citations and is from a domain leading peer-reviewed journal.
id: O60234
gene_symbol: GMFG
product_type: PROTEIN
status: COMPLETE
taxon:
id: NCBITaxon:9606
label: Homo sapiens
description: >-
GMFG encodes glia maturation factor gamma, an ADF-H/cofilin-like GMF-family
actin regulator that binds the Arp2/3 complex and remodels branched actin
networks. The strongest current evidence supports Arp2/3 binding, inhibition
of Arp2/3-mediated nucleation, and actin filament debranching at cortical and
immune-cell actin structures, with downstream roles in leukocyte migration,
integrin trafficking, immune synapse remodeling, and BCR signaling.
existing_annotations:
- term:
id: GO:0071933
label: Arp2/3 complex binding
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
This IBA annotation captures the best-supported molecular function of
GMFG as an Arp2/3 complex-binding GMF-family actin network remodeling
factor.
action: ACCEPT
reason: >-
Falcon research, InterPro/UniProt domain context, and phylogenetic
annotation converge on GMFG functioning through Arp2/3 binding rather
than as a generic glial growth factor.
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
GMFG is an ADF-H family protein that binds the Arp2/3 complex rather
than actin itself; it inhibits Arp2/3-dependent nucleation and
catalyzes debranching/pruning of daughter filaments at branch
junctions.
- term:
id: GO:0030864
label: cortical actin cytoskeleton
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
Cortical actin cytoskeleton is an appropriate active site for GMFG's
Arp2/3-dependent branched actin remodeling function.
action: ACCEPT
reason: >-
GMFG is discussed as cytosolic and enriched at actin remodeling sites
such as leading edges, immune synapses, and focal adhesions; cortical
actin cytoskeleton is the most specific existing GOA location.
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
Across experimental contexts, GMFgamma is primarily discussed as a
cytosolic protein enriched at actin remodeling sites
- term:
id: GO:0071846
label: actin filament debranching
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
Actin filament debranching is a core biological process for GMFG/GMF
family proteins acting on Arp2/3-branched actin networks.
action: ACCEPT
reason: >-
This term is specific and mechanistically aligned with GMFG's conserved
Arp2/3-regulatory activity.
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
Debranching: removal/dissociation of the daughter filament at an
Arp2/3-mediated branch junction, which contributes to turnover of
branched actin arrays and recycling of Arp2/3.
- term:
id: GO:0034316
label: negative regulation of Arp2/3 complex-mediated actin nucleation
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
This annotation captures the inhibitory arm of GMFG function toward
Arp2/3-mediated nucleation.
action: ACCEPT
reason: >-
The term is mechanistically specific and complements the debranching
annotation; both are part of GMF-family remodeling of branched actin
arrays.
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
A central concept is that branched actin networks (e.g.,
lamellipodia) are nucleated by Arp2/3 complex, and GMF proteins can
both (i) inhibit Arp2/3-mediated nucleation and (ii) catalyze
debranching/pruning
- term:
id: GO:0007165
label: signal transduction
evidence_type: IEA
original_reference_id: GO_REF:0000108
review:
summary: >-
This broad IEA appears to derive from the legacy "growth factor" view of
GMF proteins rather than from GMFG's current mechanistic annotation.
action: MARK_AS_OVER_ANNOTATED
reason: >-
GMFG can affect immune signaling through actin remodeling, but signal
transduction is too broad and indirect for the protein's core molecular
role.
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
Human GMFG (GMFgamma) is an ADF-H/cofilin-like Arp2/3-binding
regulator that remodels branched actin networks
- term:
id: GO:0003779
label: actin binding
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
The ADF-H domain supports a relationship to actin-network regulation, but
Falcon research indicates that the more precise molecular target for GMFG
is the Arp2/3 complex rather than generic actin binding.
action: MODIFY
reason: >-
Replace this generic term with the more informative Arp2/3 complex
binding term, which is already present in GOA and better describes GMFG's
core molecular function.
proposed_replacement_terms:
- id: GO:0071933
label: Arp2/3 complex binding
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
GMFG is an ADF-H family protein that binds the Arp2/3 complex rather
than actin itself
- term:
id: GO:0008083
label: growth factor activity
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
The growth factor activity annotation reflects the historical protein
name rather than current mechanistic evidence for human GMFG.
action: REMOVE
reason: >-
GMFG lacks evidence for secreted growth factor molecular activity in the
current review context; its supported role is intracellular Arp2/3 and
actin-network remodeling.
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
GMFG is best positioned as a mechanistic node and candidate biomarker
rather than a validated therapeutic target.
- term:
id: GO:0071846
label: actin filament debranching
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
The InterPro2GO IEA agrees with the IBA annotation and with the
GMF-family mechanistic literature.
action: ACCEPT
reason: >-
Actin filament debranching is a specific, core biological process for
GMFG and is supported by family/domain evidence.
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
Human GMFG (GMFgamma) is an ADF-H/cofilin-like Arp2/3-binding
regulator that remodels branched actin networks by inhibiting
Arp2/3-dependent nucleation and catalyzing debranching
- term:
id: GO:0071933
label: Arp2/3 complex binding
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
The InterPro2GO Arp2/3 complex binding annotation is consistent with the
stronger IBA annotation and the falcon-summarized literature.
action: ACCEPT
reason: >-
This is the most informative molecular-function annotation currently in
GMFG GOA.
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
Biochemical and structural work summarized in an authoritative review
indicates that GMF binds the Arp2/3 complex at two sites
- term:
id: GO:0005576
label: extracellular region
evidence_type: TAS
original_reference_id: Reactome:R-HSA-6798748
review:
summary: >-
Reactome links GMFG to neutrophil degranulation/exocytosis datasets,
where proteins can be released or detected extracellularly.
action: KEEP_AS_NON_CORE
reason: >-
This may reflect immune-cell granule/exocytosis context, but the core
functional location for GMFG is intracellular actin-remodeling sites.
supported_by:
- reference_id: file:human/GMFG/GMFG-uniprot.txt
supporting_text: Reactome; R-HSA-6798695; Neutrophil degranulation.
- term:
id: GO:0005576
label: extracellular region
evidence_type: TAS
original_reference_id: Reactome:R-HSA-6800434
review:
summary: >-
Duplicate Reactome extracellular-region annotation from ficolin-rich
granule exocytosis context.
action: KEEP_AS_NON_CORE
reason: >-
Retain as non-core Reactome localization evidence; it should not displace
the intracellular cortical actin cytoskeleton as the functional site.
supported_by:
- reference_id: file:human/GMFG/GMFG-uniprot.txt
supporting_text: Reactome; R-HSA-6798695; Neutrophil degranulation.
- term:
id: GO:0034774
label: secretory granule lumen
evidence_type: TAS
original_reference_id: Reactome:R-HSA-6798748
review:
summary: >-
This Reactome location may reflect detection in neutrophil granule
contents rather than the site of GMFG's actin-remodeling activity.
action: KEEP_AS_NON_CORE
reason: >-
GMFG is relevant to immune cells, but its core function remains
intracellular Arp2/3/actin network regulation.
supported_by:
- reference_id: file:human/GMFG/GMFG-uniprot.txt
supporting_text: Reactome; R-HSA-6798695; Neutrophil degranulation.
- term:
id: GO:1904813
label: ficolin-1-rich granule lumen
evidence_type: TAS
original_reference_id: Reactome:R-HSA-6800434
review:
summary: >-
Ficolin-1-rich granule lumen is plausible as Reactome immune-cell context
but is not the primary functional site for GMFG.
action: KEEP_AS_NON_CORE
reason: >-
Retain as non-core granule-context annotation while emphasizing cortical
actin cytoskeleton and cytosolic actin-remodeling locations as core.
supported_by:
- reference_id: file:human/GMFG/GMFG-uniprot.txt
supporting_text: Reactome; R-HSA-6798695; Neutrophil degranulation.
- term:
id: GO:0004860
label: protein kinase inhibitor activity
evidence_type: TAS
original_reference_id: PMID:8639570
review:
summary: >-
The cited study tested phosphorylated GMF as an in vitro ERK inhibitor,
but it predates GMFG-specific isolation and does not establish this as a
human GMFG molecular function.
action: REMOVE
reason: >-
This annotation is not transferable to GMFG: the cited in vitro work
used recombinant GMF described as a brain protein, consistent with the
brain-expressed GMFB isoform rather than immune-cell-expressed GMFG.
Current GMFG evidence supports Arp2/3/actin-network remodeling instead.
supported_by:
- reference_id: PMID:8639570
supporting_text: >-
recombinant glia maturation factor (GMF), a 17-kDa brain protein,
inhibits the activity of mitogen-activated protein (MAP) kinase in
the test tube assay
- term:
id: GO:0006468
label: protein phosphorylation
evidence_type: TAS
original_reference_id: PMID:7598724
review:
summary: >-
This is a substrate/process misannotation: the cited paper describes GMF
being phosphorylated by kinases, not GMFG catalyzing protein
phosphorylation.
action: REMOVE
reason: >-
GMFG is not a kinase. The cited evidence supports post-translational
regulation of GMF proteins, not assignment of the phosphorylation
biological process to GMFG as an actor.
supported_by:
- reference_id: PMID:7598724
supporting_text: >-
recombinant glia maturation factor (GMF), a 17-kD brain protein, can
be phosphorylated in vitro at the serine residue by protein kinase C
(PKC), protein kinase A (PKA), and casein kinase II (CKII)
- term:
id: GO:0008047
label: enzyme activator activity
evidence_type: TAS
original_reference_id: PMID:8798479
review:
summary: >-
The cited work reports in vitro activation of p38 MAP kinase by
phosphorylated GMF, but does not support enzyme activator activity as a
current core function for GMFG.
action: REMOVE
reason: >-
This legacy activity is not transferable to GMFG: the cited
phosphorylated-GMF experiments reflect brain-derived/brain-expressed
GMF biology, which is most consistent with GMFB rather than
immune-cell-expressed GMFG. Current GMFG evidence supports
Arp2/3-dependent actin network remodeling.
supported_by:
- reference_id: PMID:8798479
supporting_text: >-
PKA-phosphorylated GMF strongly enhances the activity of a related
but distinct subfamily of MAP kinase, the p38 MAP kinase
references:
- id: GO_REF:0000002
title: Gene Ontology annotation through association of InterPro records with GO terms
findings: []
- id: GO_REF:0000033
title: Annotation inferences using phylogenetic trees
findings: []
- id: GO_REF:0000043
title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
findings: []
- id: GO_REF:0000108
title: Automatic assignment of GO terms using logical inference, based on on inter-ontology links
findings: []
- id: PMID:7598724
title: Phorbol ester stimulates rapid intracellular phosphorylation of glia maturation factor.
findings:
- statement: GMF proteins are phosphorylated substrates rather than kinases.
supporting_text: >-
recombinant glia maturation factor (GMF), a 17-kD brain protein, can be
phosphorylated in vitro at the serine residue by protein kinase C
(PKC), protein kinase A (PKA), and casein kinase II (CKII)
- id: PMID:8639570
title: In vitro inhibition of MAP kinase (ERK1/ERK2) activity by phosphorylated glia maturation factor (GMF).
findings:
- statement: Phosphorylated GMF inhibited ERK in vitro, but this is not GMFG-specific evidence.
supporting_text: >-
recombinant glia maturation factor (GMF), a 17-kDa brain protein,
inhibits the activity of mitogen-activated protein (MAP) kinase in the
test tube assay
- id: PMID:8798479
title: In vitro enhancement of p38 mitogen-activated protein kinase activity by phosphorylated glia maturation factor.
findings:
- statement: Phosphorylated GMF enhanced p38 activity in vitro, a legacy non-GMFG-specific finding.
supporting_text: >-
PKA-phosphorylated GMF strongly enhances the activity of a related but
distinct subfamily of MAP kinase, the p38 MAP kinase
- id: Reactome:R-HSA-6798748
title: Exocytosis of secretory granule lumen proteins
findings: []
- id: Reactome:R-HSA-6800434
title: Exocytosis of ficolin-rich granule lumen proteins
findings: []
- id: file:human/GMFG/GMFG-uniprot.txt
title: UniProt text export for GMFG (O60234)
findings:
- statement: UniProt places GMFG in the GMF subfamily of ADF actin-binding proteins.
supporting_text: Belongs to the actin-binding proteins ADF family. GMF subfamily.
- id: file:human/GMFG/GMFG-deep-research-falcon.md
title: Falcon deep research report for GMFG
findings:
- statement: Falcon research identifies GMFG as an Arp2/3-dependent actin network remodeling factor.
supporting_text: >-
Human GMFG (GMFgamma) is an ADF-H/cofilin-like Arp2/3-binding
regulator that remodels branched actin networks
core_functions:
- description: >-
Arp2/3 complex binding and remodeling of branched cortical actin networks,
including actin filament debranching and inhibition of Arp2/3-mediated
actin nucleation.
molecular_function:
id: GO:0071933
label: Arp2/3 complex binding
directly_involved_in:
- id: GO:0071846
label: actin filament debranching
- id: GO:0034316
label: negative regulation of Arp2/3 complex-mediated actin nucleation
locations:
- id: GO:0030864
label: cortical actin cytoskeleton
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
Human GMFG (GMFgamma) is an ADF-H/cofilin-like Arp2/3-binding
regulator that remodels branched actin networks by inhibiting
Arp2/3-dependent nucleation and catalyzing debranching
- description: >-
Immune-cell actin remodeling that supports leukocyte migration, integrin
trafficking, and immune synapse dynamics, interpreted as cellular outcomes
of the same Arp2/3/branched-actin remodeling activity.
molecular_function:
id: GO:0071933
label: Arp2/3 complex binding
directly_involved_in:
- id: GO:0071846
label: actin filament debranching
locations:
- id: GO:0030864
label: cortical actin cytoskeleton
supported_by:
- reference_id: file:human/GMFG/GMFG-deep-research-falcon.md
supporting_text: >-
This places GMFG at the intersection of Arp2/3-dependent actin
remodeling and vesicular trafficking pathways that control integrin
turnover during directed migration.
proposed_new_terms: []
suggested_questions:
- question: Which human immune-cell contexts require GMFG's Arp2/3 debranching activity directly, rather than indirect effects on integrin trafficking?
- question: Are the Reactome granule/extracellular annotations true GMFG localization states or proteomics carryover from neutrophil degranulation datasets?
- question: Do historical MAPK inhibitor/activator findings apply to GMFG specifically, or only to GMFB/undifferentiated GMF preparations?
suggested_experiments:
- description: Endogenous GMFG tagging in primary monocytes and B cells followed by live imaging of Arp2/3, F-actin, and integrin recycling during chemotaxis or immune synapse formation.
experiment_type: live-cell imaging/genome editing
hypothesis: GMFG localizes to cortical actin remodeling sites where Arp2/3-dependent debranching supports immune-cell migration and synapse dynamics.
- description: Biochemical reconstitution comparing purified human GMFG and GMFB for Arp2/3 binding, nucleation inhibition, and branch deassembly using TIRF microscopy.
experiment_type: biochemical reconstitution
hypothesis: GMFG has direct Arp2/3-regulatory activity comparable to other GMF-family proteins and does not require legacy MAPK-modulatory activity to explain its core function.
- description: Proteomic reanalysis of neutrophil granule/extracellular fractions with endogenous GMFG controls and cytosolic contamination markers.
experiment_type: proteomics/localization validation
hypothesis: Reactome granule/extracellular annotations reflect immune-cell degranulation datasets rather than the primary functional location of GMFG.