Affinage

RGS20

Regulator of G-protein signaling 20 · UniProt O76081

Length
388 aa
Mass
43.7 kDa
Annotated
2026-06-10
21 papers in source corpus 18 papers cited in narrative 19 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 8/8 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

RGS20 (RGSZ1) is a membrane-bound GTPase-activating protein of the RZ subfamily of RGS proteins that functions as a highly selective negative regulator of Gz-coupled G protein signaling (PMID:9748280, PMID:9748279). It accelerates hydrolysis of Gαz-GTP over 400-fold with ~100-fold selectivity for Gαz over Gαi, and its regulatory activity depends on stable bilayer association (PMID:9748280); RGSZ1 and Ret RGS arise as splice variants of the single RGS20 gene (PMID:11735229). Although Gz-selective, RGS20 also engages Gαi subunits in an activation-dependent manner and dampens receptor-driven MAPK and SRE signaling (PMID:12379657). RGS20 activity is tuned by multiple inputs: PKC phosphorylation of Gαz inhibits its GAP activity (PMID:9748280, PMID:9748279), palmitoylation of a conserved RGS-domain cysteine enhances association with active Gαo and inhibition of Gαo-cAMP signaling through a non-GAP mechanism (PMID:37075876), and activated Gαo/Gαi2 promote RGS20 ubiquitination and proteasomal degradation, allowing receptor-driven cross-pathway signal integration (PMID:18407463). Within GPCR complexes, RGS20 pre-associates with melatonin MT1 receptor dimers and Gi in an asymmetric architecture, occupying a separate protomer from the coupled G protein (PMID:20859254). In the CNS, RGS20 constrains mu opioid receptor signaling and morphine antinociception, and chronic morphine drives RGSz1 activity in the periaqueductal gray to promote analgesic tolerance via Gαz/Axin2/Wnt–β-catenin cross-talk, while circuit-specific RGSz1 in vlPAG-to-VTA projections modulates opioid reward (PMID:14997173, PMID:29440403, PMID:36310031). In cancer, RGS20 acts as a proliferative driver through physical interaction with the PI3K p85α subunit and PI3K/AKT activation (PMID:35498542), inhibition of PKA-Hippo signaling to promote YAP nuclear translocation (PMID:38431606), and ligand-independent WNT/β-catenin activation supporting tumor stemness and drug resistance (PMID:41315804); its transcription is driven by SP1 super-enhancer phase separation (PMID:38976739). RGS20 additionally binds the microtubule-destabilizing protein SCG10 and blocks SCG10-induced microtubule disassembly (PMID:11882662).

Mechanistic history

Synthesis pass · year-by-year structured walk · 14 steps
  1. 1998 High

    Established the core biochemical identity of RGS20 as a Gz-selective GAP, answering what molecular activity this protein carries and on which G protein it acts.

    Evidence In vitro GTPase assays with purified protein, phospholipid vesicle reconstitution with Gz and m2 receptors, and yeast two-hybrid against constitutively active Gαz

    PMID:9748279 PMID:9748280

    Open questions at the time
    • Did not define structural basis of Gαz selectivity
    • Cellular regulatory inputs not yet identified
  2. 1998 High

    Identified the first regulatory input on RGS20 GAP activity, showing PKC phosphorylation of the Gαz substrate inhibits GAP function and thereby potentiates Gz signaling.

    Evidence In vitro GTPase assay using PKC-phosphorylated Gαz and purified recombinant RGSZ1

    PMID:9748279 PMID:9748280

    Open questions at the time
    • Phosphorylation acts on substrate, not RGS20 directly
    • In vivo relevance of this regulation not tested
  3. 2001 High

    Resolved the gene architecture, showing RGSZ1 and Ret RGS are splice variants of one RGS20 gene, explaining observed protein heterogeneity.

    Evidence Genomic cloning, exon mapping, RT-PCR and Northern blot across tissues

    PMID:11735229

    Open questions at the time
    • Functional distinction between isoforms not established
  4. 2002 High

    Broadened the substrate and functional scope by showing RGS20 also acts on Gαi and attenuates receptor-driven MAPK/SRE signaling, and that it binds the microtubule-destabilizing protein SCG10.

    Evidence Pull-down, co-IP, yeast two-hybrid, single-turnover GTPase, cell-based MAPK/SRE reporters, and in vitro microtubule polymerization assays with Golgi localization imaging

    PMID:11882662 PMID:12379657

    Open questions at the time
    • Physiological significance of SCG10 binding in neurons not established
    • Relative contribution of Gi versus Gz regulation in cells unclear
  5. 2004 Medium

    Established a physiological role in opioid signaling, showing RGS20 constrains mu opioid receptor-mediated antinociception and modulates tolerance in vivo.

    Evidence Antisense oligodeoxynucleotide knockdown in mouse CNS with antinociception behavioral assays

    PMID:14997173

    Open questions at the time
    • Single lab and single knockdown method
    • Direct biochemical link to Gαz in this context not shown
  6. 2006 Medium

    Identified protein partners (PKCI-1, 14-3-3) coupling RGS20 to the PKC/Gαz phosphorylation axis and showed enhanced suppression of MOPR-cAMP signaling.

    Evidence Yeast two-hybrid, co-IP, immunofluorescence, and cAMP functional assays

    PMID:17126529

    Open questions at the time
    • Single lab
    • Stoichiometry and direct structural basis of the competition for 14-3-3 not resolved
  7. 2008 Medium

    Defined a feedback degradation mechanism in which activated Gαo/Gαi2 trigger RGS20 ubiquitination and proteasomal turnover, enabling cross-pathway signal integration.

    Evidence Co-IP, proteasome inhibitor rescue, ubiquitination assay, cAMP functional assay

    PMID:18407463

    Open questions at the time
    • E3 ligase responsible for ubiquitination not identified
    • Single lab
  8. 2010 High

    Provided structural insight into how RGS20 is organized within GPCR complexes, revealing an asymmetric pre-associated MT1 dimer-Gi-RGS20 architecture.

    Evidence BRET with multi-site probe insertion, cross-validated with MT1/MT2 heterodimers

    PMID:20859254

    Open questions at the time
    • No atomic-resolution structure
    • Generality across other receptor dimers not established
  9. 2014 Medium

    Linked hormone/estrogen signaling to RGS20 regulation via post-translational modification and membrane microdomain targeting controlling 5-HT1A receptor signaling.

    Evidence DRM fractionation, immunoblotting for SUMOylation/glycosylation, and in vivo hormone release assays (also building on 2012 estradiol findings)

    PMID:22251927 PMID:25402859

    Open questions at the time
    • Direct enzymes mediating SUMOylation/glycosylation not identified
    • Causal link between DRM localization and Gαz inactivation inferred
  10. 2018 High

    Established the in vivo circuit and transcriptional mechanism by which RGS20 controls morphine tolerance through Gαz/Axin2/Wnt-β-catenin cross-talk in the periaqueductal gray.

    Evidence Global and region-targeted RGSz1 mouse models, biochemical assays, RNA-seq, and viral delivery

    PMID:29440403

    Open questions at the time
    • Molecular basis of Axin2-Gαz complex stabilization incomplete
    • Direct GAP-versus-scaffold contribution not dissected
  11. 2022 High

    Extended circuit-level and biochemical selectivity findings, confirming RGSz1 selectively impedes MOPR-mediated Gαz signaling and modulates opioid reward.

    Evidence Cre-dependent circuit-specific viral knockdown, conditioned place preference, BRET sensors, and PAG membrane cAMP assays

    PMID:36310031

    Open questions at the time
    • Downstream effectors in VTA projection not fully mapped
  12. 2023 Medium

    Uncovered palmitoylation of a conserved RGS-domain cysteine as a GAP-independent regulatory mechanism enhancing Gαo association and inhibition.

    Evidence Palmitoylation assay, cysteine mutagenesis, co-IP with active Gαo, and cAMP functional assays

    PMID:37075876

    Open questions at the time
    • Palmitoyltransferase responsible not identified
    • Single lab
  13. 2024 Medium

    Established RGS20 as a cancer driver and defined its transcriptional control, linking SP1 super-enhancer phase separation to RGS20 expression and RGS20 to PI3K/AKT and PKA-Hippo-YAP signaling.

    Evidence CUT&RUN, phase separation and reporter assays, co-IP with PI3K p85α, epistasis rescue, transcriptomics, and xenograft models (also penile cancer p85α study)

    PMID:35498542 PMID:38431606 PMID:38976739

    Open questions at the time
    • Mechanistic link between RGS20 GAP/G-protein activity and PI3K or Hippo regulation unresolved
    • Single lab per cancer context
  14. 2025 Medium

    Connected RGS20 loss to ligand-independent WNT/β-catenin activation driving glioma stemness and drug resistance in hypoxic niches.

    Evidence Sphere formation, stem marker expression, knockdown/overexpression, in vivo tumor model, and human glioblastoma specimens

    PMID:41315804

    Open questions at the time
    • No biochemical mechanism for how RGS20 represses β-catenin established
    • Single lab

Open questions

Synthesis pass · forward-looking unresolved questions
  • It remains unresolved how RGS20's defined Gαz/Gαi GAP and palmitoylation-dependent activities mechanistically connect to the PI3K/AKT, PKA-Hippo-YAP, and WNT/β-catenin pathways it controls in cancer, and which E3 ligase and modifying enzymes govern its turnover and PTMs.
  • No structural model of RGS20 in GPCR complexes at atomic resolution
  • Direct biochemical bridge between G-protein regulation and oncogenic signaling pathways missing
  • Enzymes mediating ubiquitination, SUMOylation, glycosylation, and palmitoylation unidentified

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0098772 molecular function regulator activity 4 GO:0140096 catalytic activity, acting on a protein 3 GO:0008092 cytoskeletal protein binding 1
Localization
GO:0005886 plasma membrane 3 GO:0005794 Golgi apparatus 1
Pathway
R-HSA-162582 Signal Transduction 4 R-HSA-112316 Neuronal System 3
Partners
GNAI2GNAO1GNAZHINT1/PKCI-1MTNR1A/MT1PIK3R1/P85ΑSCG10/STMN2YWHA/14-3-3
Complex memberships
MT1 receptor dimer–Gi–RGS20 ternary complex

Evidence

Reading pass · 19 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1998 RGSZ1 (RGS20) is a Gz-selective GTPase-activating protein (GAP) that accelerates hydrolysis of Gαz-GTP over 400-fold with Km ~2 nM, shows 100-fold selectivity for Gαz over Gαi, and when co-reconstituted into phospholipid vesicles with Gz and m2 muscarinic receptors increased agonist-stimulated GTPase >15-fold. RGSZ1 is tightly membrane-bound in brain and its regulatory activity depends on stable bilayer association. In vitro GTPase assay with purified recombinant protein, phospholipid vesicle reconstitution, membrane fractionation The Journal of biological chemistry High 9748280
1998 Phosphorylation of Gαz by protein kinase C (PKC) inhibits the GAP activity of RGSZ1 (RGS20) toward Gαz-GTP, providing a mechanism for potentiation of Gz signaling by PKC. In vitro GTPase assay using PKC-phosphorylated Gαz and purified recombinant RGSZ1 The Journal of biological chemistry High 9748279 9748280
1998 RGSZ1 (RGS20) was identified via yeast two-hybrid as a binding partner for constitutively active Gαz, confirming selective interaction with Gαz over other Gαi family members. Yeast two-hybrid screen, biochemical GAP assay with recombinant protein The Journal of biological chemistry High 9748279
2001 RGSZ1 and Ret RGS are splice variants of a single gene, RGS20, which spans ~107 kb and contains at least seven exons. Multiple translational start sites within the RGSZ1 ORF may explain molecular weight heterogeneity of purified brain RGSZ protein. Genomic cloning, exon mapping, RT-PCR, Northern blot Genomics High 11735229
2002 RGSZ1 (RGS20) interacts with Gαi subunits (not only Gαz) in an AlF4−-dependent manner and accelerates intrinsic GTPase activity of Gαi1. In PC12 cells, RGSZ1 blocks MAPK activity induced by α2-adrenergic receptor agonist, and attenuates D2 dopamine receptor agonist-induced SRE reporter activity in CHO cells. GST pull-down, co-immunoprecipitation, yeast two-hybrid with luciferase reporter, single-turnover GTPase assay, yeast pheromone response assay, MAPK assay, SRE reporter assay The Journal of biological chemistry High 12379657
2002 RGSZ1 (RGS20) directly interacts with SCG10 (a microtubule-destabilizing protein) via yeast two-hybrid and direct binding assays. Upon NGF treatment, GFP-tagged RGSZ1 translocates to the Golgi complex in PC12 cells where SCG10 is also distributed. Binding of RGSZ1 to SCG10 blocks SCG10-induced microtubule disassembly in vitro. Yeast two-hybrid, direct binding assay, GFP live-cell imaging/subcellular localization, turbidimetric and microscopy-based in vitro microtubule polymerization assay The Journal of biological chemistry High 11882662
2004 Knockdown of RGSZ1 (RGS20) with antisense oligodeoxynucleotides in mouse CNS significantly increased supraspinal antinociception by morphine, heroin, DAMGO, and endomorphin-1 (but not endomorphin-2), and extended morphine analgesia duration, while having no effect on delta opioid receptor agonists DPDPE and deltorphin II. RGSZ1 knockdown facilitated morphine tolerance development. Antisense oligodeoxynucleotide knockdown in vivo, antinociception behavioral assay Neuropsychopharmacology Medium 14997173
2006 RGSZ1 (RGS20) interacts with PKCI-1 via its N-terminal cysteine string region (shared with RZ subfamily), confirmed by co-immunoprecipitation and immunofluorescence. RGSZ1 and PKCI-1 together significantly reduce mu opioid receptor-mediated inhibition of cAMP more than RGSZ1 alone. 14-3-3 inhibits PKC-mediated phosphorylation of Gαz, and RGSZ1 competes with PKCI-1 for 14-3-3 binding. Yeast two-hybrid, co-immunoprecipitation, immunofluorescence, cAMP functional assay Cellular signalling Medium 17126529
2008 Activated Gαo and Gαi2 (but not Gαq, Gαi1, or Gαi3) interact with RGS20 and promote its proteasomal degradation via ubiquitination. Serotonin-1A receptor activation reduces RGS20 levels through this Gαo/i-proteasomal mechanism. Loss of RGS20 via this pathway reduces RGS20-mediated attenuation of Gi inhibition of β-adrenergic receptor-induced cAMP, enabling cross-pathway signal integration. Co-immunoprecipitation, proteasomal inhibitor (lactacystin, MG132) rescue experiments, ubiquitination assay, cAMP functional assay Cellular signalling Medium 18407463
2010 RGS20 forms a ternary pre-associated complex with the melatonin MT1 receptor dimer and Gi protein. BRET analysis with probes at multiple sites revealed an asymmetric architecture in which one Gi and one RGS20 bind to separate protomers of the MT1 dimer; this complex rearranges upon agonist activation. Validated with MT1/MT2 heterodimers. Bioluminescence resonance energy transfer (BRET) with multi-site probe insertion, validated with heterodimers The EMBO journal High 20859254
2012 Estradiol benzoate treatment increases a 55 kDa membrane-associated RGSZ1 (RGS20) protein in the paraventricular nucleus of the hypothalamus and other brain regions, associated with partial desensitization of 5-HT1A receptor signaling as measured by reduced oxytocin and ACTH release. Western blotting, subcellular fractionation, in vivo hormone release assay Neuropharmacology Medium 22251927
2014 GPER1 stimulation alters post-translational modifications of RGSz1 (RGS20): high-molecular-weight RGSz1 isoforms are SUMOylated and glycosylated, localize to detergent-resistant membrane microdomains (DRM), and are increased by estradiol and G-1 treatment. Activated Gαz also localizes to DRM, so increased DRM-localized RGSz1 is proposed to reduce Gαz activity and functionally uncouple 5-HT1AR signaling. Subcellular fractionation (DRM isolation), immunoblotting for SUMOylation/glycosylation/phosphorylation, in vivo hormone release functional assay Neuroendocrinology Medium 25402859
2018 Chronic morphine administration promotes RGSz1 (RGS20) activity in the periaqueductal gray (PAG), which modulates Wnt/β-catenin transcriptional signaling to promote analgesic tolerance. Suppression of RGSz1 stabilizes Axin2-Gαz complexes near the membrane and promotes β-catenin activation, delaying morphine tolerance. Genetic mouse models (global and brain region-targeted RGSz1 knockout/knockdown), biochemical assays, next-generation RNA sequencing, viral vector delivery Proceedings of the National Academy of Sciences of the United States of America High 29440403
2022 RGS20 interacts physically with the PI3K p85α subunit in penile cancer cell lines and regulates PI3K/AKT signaling activation. Knockdown of PI3K p85α or p110α phenocopies RGS20 depletion, while expression of constitutively active PI3K p110α rescues proliferation and migration defects caused by RGS20 depletion. Co-immunoprecipitation, siRNA knockdown, constitutively active PI3K overexpression rescue, xenograft tumor model Journal of oncology Medium 35498542
2022 RGSz1 (RGS20) in vlPAG projections to the VTA modulates morphine reward. BRET sensor experiments demonstrate RGSz1 selectively modulates Gαz (but not other Gαi family subunits) and impedes MOPR-mediated Gαz signaling; RGSz1 KO enhances opioid-induced cAMP inhibition in PAG membranes. Cre-dependent viral vector knockdown in specific brain circuits, conditioned place preference assay, BRET sensors, cAMP inhibition assay in PAG membranes Molecular pharmacology High 36310031
2023 RGS20 is palmitoylated, and a conserved cysteine residue in the RGS domain is a critical palmitoylation site. Palmitoylation increases RGS20 association with active Gαo but does not affect GAP activity per se; however, palmitoylation increases inhibition of Gαo-mediated cAMP signaling, indicating a non-GAP mechanism of Gαo regulation by RGS20. Palmitoylation assay, site-directed mutagenesis of cysteine residues, co-immunoprecipitation with active Gαo, cAMP functional assay Cellular signalling Medium 37075876
2024 SP1 undergoes phase separation and activates RGS20 transcription through super-enhancer (SE) mechanisms. CUT&RUN identified RGS20 as the top SP1/H3K27ac SE target in lung adenocarcinoma; SP1 zinc finger 3 in the DNA-binding domain is essential for phase separation. The demethylase inhibitor GSK-J4 abolishes SP1 phase separation and RGS20 activation. CUT&RUN (SP1 and H3K27ac), phase separation assay, domain deletion mutagenesis, GSK-J4 inhibitor treatment, reporter assays Proceedings of the National Academy of Sciences of the United States of America Medium 38976739
2024 RGS20 promotes NSCLC cell proliferation by inhibiting PKA-Hippo signaling, reducing YAP phosphorylation and facilitating its nuclear translocation, and by activating autophagy. Forskolin (a GPCR/PKA activator) increased YAP phosphorylation and reversed the proliferative effect of RGS20 overexpression. Transcriptome sequencing, immunofluorescence for YAP nuclear translocation, Western blotting, Hippo pathway inhibitor (GA-017), PKA activator (forskolin) rescue, in vivo xenograft Cancer cell international Medium 38431606
2025 RGS20 inhibition in glioma cells intrinsically activates WNT/β-catenin signaling in a ligand-independent manner, enhancing tumor sphere formation, upregulating stem cell markers, and promoting temozolomide resistance. This mechanism operates in hypoxic niches where β-catenin signaling is enriched with low RGS20 expression. In vitro sphere formation, stem cell marker expression, in vivo tumor model, human glioblastoma specimen analysis, RGS20 knockdown/overexpression Scientific reports Medium 41315804

Source papers

Stage 0 corpus · 21 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1998 RGSZ1, a Gz-selective RGS protein in brain. Structure, membrane association, regulation by Galphaz phosphorylation, and relationship to a Gz gtpase-activating protein subfamily. The Journal of biological chemistry 128 9748280
1998 RGSZ1, a Gz-selective regulator of G protein signaling whose action is sensitive to the phosphorylation state of Gzalpha. The Journal of biological chemistry 108 9748279
2018 lncRNA NEAT1 promotes cell proliferation and invasion by regulating miR‑365/RGS20 in oral squamous cell carcinoma. Oncology reports 63 29484420
2010 Molecular organization and dynamics of the melatonin MT₁ receptor/RGS20/G(i) protein complex reveal asymmetry of receptor dimers for RGS and G(i) coupling. The EMBO journal 57 20859254
2006 RGSZ1 interacts with protein kinase C interacting protein PKCI-1 and modulates mu opioid receptor signaling. Cellular signalling 52 17126529
2004 RGSZ1 and GAIP regulate mu- but not delta-opioid receptors in mouse CNS: role in tachyphylaxis and acute tolerance. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology 49 14997173
2002 Regulator of G protein signaling Z1 (RGSZ1) interacts with Galpha i subunits and regulates Galpha i-mediated cell signaling. The Journal of biological chemistry 40 12379657
2002 The interaction of RGSZ1 with SCG10 attenuates the ability of SCG10 to promote microtubule disassembly. The Journal of biological chemistry 32 11882662
2001 RGSZ1 and Ret RGS: two of several splice variants from the gene RGS20. Genomics 31 11735229
2018 Suppression of RGSz1 function optimizes the actions of opioid analgesics by mechanisms that involve the Wnt/β-catenin pathway. Proceedings of the National Academy of Sciences of the United States of America 26 29440403
2024 SP1 undergoes phase separation and activates RGS20 expression through super-enhancers to promote lung adenocarcinoma progression. Proceedings of the National Academy of Sciences of the United States of America 22 38976739
2014 GPER1 stimulation alters posttranslational modification of RGSz1 and induces desensitization of 5-HT1A receptor signaling in the rat hypothalamus. Neuroendocrinology 15 25402859
2012 Estradiol induces partial desensitization of serotonin 1A receptor signaling in the paraventricular nucleus of the hypothalamus and alters expression and interaction of RGSZ1 and Gαz. Neuropharmacology 14 22251927
2022 RGS20 Promotes Tumor Progression through Modulating PI3K/AKT Signaling Activation in Penile Cancer. Journal of oncology 13 35498542
2024 RGS20 promotes non-small cell lung carcinoma proliferation via autophagy activation and inhibition of the PKA-Hippo signaling pathway. Cancer cell international 11 38431606
2008 Galphao/i-stimulated proteosomal degradation of RGS20: a mechanism for temporal integration of Gs and Gi pathways. Cellular signalling 11 18407463
2022 A Regional and Projection-Specific Role of RGSz1 in the Ventrolateral Periaqueductal Grey in the Modulation of Morphine Reward. Molecular pharmacology 8 36310031
2004 Analysis of the regulation of microtubule dynamics by interaction of RGSZ1 (RGS20) with the neuronal stathmin, SCG10. Methods in enzymology 8 15488170
2023 Palmitoylation of RGS20 affects Gαo-mediated signaling independent of its GAP activity. Cellular signalling 6 37075876
2004 Analysis of RGSZ1 protein interaction with Galphai subunits. Methods in enzymology 2 15488169
2025 RGS20 reduces glioma stemness and temozolomide resistance by intrinsically inhibiting the WNT/β-catenin signaling pathway. Scientific reports 0 41315804

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