Affinage

SNRPD2

Small nuclear ribonucleoprotein Sm D2 · UniProt P62316

Length
118 aa
Mass
13.5 kDa
Annotated
2026-06-10
28 papers in source corpus 13 papers cited in narrative 13 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

SNRPD2 (Sm-D2) is a core Sm protein of the spliceosome that participates in U snRNP assembly and pre-mRNA splicing, and through this activity controls the alternative splicing and processing of multiple cancer-relevant transcripts (PMID:33648524, PMID:35417229). Within the spliceosomal machinery it cooperates with partner factors—it physically binds HNRNPL to modulate DDX39A intron retention (PMID:39018261) and binds mutant p53 to facilitate assembly of the Sm/SMN complex that underlies splicing of pre-mRNAs such as OTUD3 (PMID:41560375). SNRPD2 governs specific splicing decisions whose disruption couples to nonsense-mediated decay: its loss drives intron retention in DDX39B and exon skipping in CPSF7, generating NMD-targeted transcripts that in turn reshape downstream targets (CTSC, UBE2K) (PMID:41720762, PMID:42098443), and it regulates intron 1 retention of sororin to control sister chromatid cohesion (PMID:33648524). Beyond splicing, SNRPD2 influences alternative polyadenylation: free U1 snRNP-associated SNRPD2 promotes proximal poly(A) site usage (PMID:36073763), and it interacts with the EP domain of PABPN1 to disrupt PABPN1 liquid-liquid phase separation, relieving repression of proximal poly(A) sites (PMID:38811444). SNRPD2 is upregulated and behaves as an oncogene in hepatocellular and other cancers, sustained by a MYC positive-feedback loop and repressed transcriptionally by NKRF, and its depletion is selectively lethal to cancer cells (PMID:39018261, PMID:39684842, PMID:42026030). Developmentally, programmed low SNRPD2 expression at zygotic genome activation produces transient splicing failure that attenuates the p53-mediated DNA damage response (PMID:35417229). SNRPD2 is also recognized by anti-Sm autoantibodies in systemic lupus erythematosus, with antigenic epitopes distinct from other Sm-D family members (PMID:10444365).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 1999 Medium

    Established Sm-D2 as an autoantigen distinct from other Sm-D family members, defining its independent antigenic identity within the Sm protein family.

    Evidence Immunoblot and monoclonal antibody screening of human/murine lupus sera plus immunization with isolated Sm-D antigen

    PMID:10444365

    Open questions at the time
    • Purely serological; no biochemical or structural mechanism
    • Does not address SNRPD2's role in splicing
  2. 2021 Medium

    Placed SNRPD2 in a spliceosome complex whose function controls sister chromatid cohesion via sororin intron retention, linking a core Sm protein to a defined splicing-dependent phenotype in cancer.

    Evidence RNAi screen, intron-retention PCR, FACS, and pulldown/MS in triple-negative breast cancer cells

    PMID:33648524

    Open questions at the time
    • Role of novel component SUN2 in splicing not mechanistically resolved
    • Direct vs indirect effect on sororin splicing not separated
  3. 2022 Medium

    Demonstrated that developmentally programmed low SNRPD2 expression causes splicing failure that attenuates the p53 DNA damage response, establishing a physiological consequence of limiting this Sm protein.

    Evidence Cross-species embryo transcriptomics and mRNA microinjection rescue in mouse zygotes

    PMID:35417229

    Open questions at the time
    • Specific exon-skipping targets driving DDR attenuation not enumerated
    • Snrpb vs Snrpd2 individual contributions not separated
  4. 2022 Medium

    Identified SNRPD2 as a host substrate of the Salmonella effector E3 ligase SlrP, revealing a pathogen-targeted post-translational modification of the spliceosome.

    Evidence Yeast two-hybrid binding, in vitro ubiquitination assay, and MS lysine-site mapping

    PMID:36290420

    Open questions at the time
    • Functional consequence of SNRPD2 ubiquitination on splicing not determined
    • In vivo relevance during infection not shown
  5. 2022 Medium

    Showed that free (non-complexed) SNRPD2 promotes proximal alternative polyadenylation, distinguishing the activity of dissociated U1 snRNP subunits from the intact complex.

    Evidence Knockdown/overexpression with transcriptome-wide APA profiling, phase transition and Co-IP assays

    PMID:36073763

    Open questions at the time
    • 3' end processing machinery contacts not mapped at residue level
    • Genome-wide rules for proximal site selection unresolved
  6. 2024 Medium

    Defined SNRPD2 as an HCC oncogene operating through an HNRNPL-dependent DDX39A splicing switch and a MYC positive-feedback loop, and a druggable target of digitoxin.

    Evidence Knockdown/overexpression, intron-retention and MYC mRNA export assays, drug-binding assay, in vivo tumor models

    PMID:39018261

    Open questions at the time
    • Digitoxin binding site and selectivity not structurally defined
    • Direct vs indirect MYC transcriptional activation not separated
  7. 2024 Medium

    Established a non-splicing mechanism whereby SNRPD2 binds the PABPN1 EP domain to disrupt its phase separation and relieve APA repression, linking SNRPD2 to 3' UTR shortening in colorectal cancer.

    Evidence Co-IP, domain mapping, LLPS assay, APA profiling, and proliferation/migration assays

    PMID:38811444

    Open questions at the time
    • Stoichiometry and reversibility of LLPS disruption unclear
    • Single downstream target (CTNNBIP1) characterized in detail
  8. 2024 Medium

    Demonstrated cancer-selective lethality of SNRPD2 depletion and correlated its essentiality profile with mRNA splicing, protein production, and mitosis.

    Evidence shRNA lentiviral knockdown across cancer and normal cells plus DepMap essentiality-profile correlation

    PMID:39684842

    Open questions at the time
    • Basis for cancer-selective dependency not mechanistically explained
    • Correlative essentiality does not establish direct pathway membership
  9. 2026 Medium

    Showed mutant p53 physically binds SNRPD2 to promote Sm/SMN complex assembly and redirect OTUD3 splicing toward oncogenic isoforms, coupling a transcription factor to spliceosome assembly.

    Evidence Co-IP, overexpression/depletion, OTUD3 exon-skipping analysis, xenograft with exosome-delivered siRNA

    PMID:41560375

    Open questions at the time
    • Whether wild-type p53 has the same activity not addressed
    • Direct effect on snRNP assembly kinetics not quantified
  10. 2026 Medium

    Defined a SNRPD2-DDX39B-CTSC axis in which SNRPD2 loss triggers intron retention and NMD of DDX39B, derepressing a cryptic exon in CTSC, demonstrating cascading splicing-NMD control.

    Evidence Knockdown, intron-retention/cryptic-exon analysis, NMD assays, ASO treatment, PDX model

    PMID:41720762

    Open questions at the time
    • Direct SNRPD2 binding on DDX39B pre-mRNA not shown
    • Breadth of CTSC-dependent downstream effects unmapped
  11. 2026 Medium

    Defined a SNRPD2-CPSF7-UBE2K axis linking SNRPD2-controlled CPSF7 exon skipping to downstream APA in ovarian cancer, connecting splicing to polyadenylation control.

    Evidence SNRPD2/CPSF7 knockdown, exon-skipping and NMD analysis, APA profiling, PDX with ASOs

    PMID:42098443

    Open questions at the time
    • Whether the CPSF7 RRM disruption is the sole driver of UBE2K APA unclear
    • Generality of this axis beyond ovarian cancer untested
  12. 2026 Medium

    Placed SNRPD2 under transcriptional control of NKRF (itself regulated by TRIM26-mediated ubiquitination), linking SNRPD2 abundance to stress granule formation and Osimertinib drug tolerance.

    Evidence Co-IP, K48/Lys411 ubiquitination assays, reporter assays, knockdown/overexpression, stress granule imaging, xenografts

    PMID:42026030

    Open questions at the time
    • Mechanism by which SNRPD2 promotes stress granule assembly not defined
    • Whether NKRF binds the SNRPD2 promoter directly not fully resolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • How SNRPD2 selects specific pre-mRNA targets for intron retention versus exon skipping, and whether its APA and stress-granule roles are separable from its core Sm spliceosome function, remains unresolved.
  • No structural model of SNRPD2 within target-specific spliceosome configurations
  • Direct RNA-binding specificity of SNRPD2 not mapped
  • Separation of canonical snRNP role from free-protein APA/phase-separation roles incomplete

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0003723 RNA binding 3 GO:0005198 structural molecule activity 2
Localization
GO:0005634 nucleus 2
Pathway
R-HSA-8953854 Metabolism of RNA 4 R-HSA-74160 Gene expression (Transcription) 2
Complex memberships
Sm/SMN complexU1 snRNPspliceosome

Evidence

Reading pass · 13 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2021 Depletion of SNRPD2 (along with SNRPD3 and NHP2L1) inhibits proliferation of triple-negative breast cancer (TNBC) cells by deregulating sister chromatid cohesion (SCC) via increased sororin intron 1 retention and downregulation of SMC1, MAU2, and ESPL1. Protein-protein interaction analysis identified SNRPD2, SNRPD3, and NHP2L1 as belonging to the same spliceosome complex, which also includes novel component SUN2, critical for efficient sororin splicing. RNAi screen, western blot, PCR (intron retention), FACS, molecular imaging, pulldown + mass spectrometry for protein-protein interactions Journal of experimental & clinical cancer research Medium 33648524
2022 Snrpb and Snrpd2 regulate exon-skipping patterns during zygotic genome activation (ZGA). These two core spliceosomal components have low maternal expression at ZGA and increase sharply thereafter. Microinjection of Snrpb/d2 mRNA into mouse zygotes reduces exon skipping at ZGA and leads to increased p53-mediated DNA damage response, establishing that developmentally programmed low expression of these factors contributes to splicing failure and attenuation of DNA damage response. Transcriptomic analysis of preimplantation embryos (human, mouse, cow), microinjection of mRNA into mouse zygotes, measurement of exon skipping and p53-mediated DDR Science advances Medium 35417229
2022 SNRPD2 is a novel substrate for the E3 ubiquitin ligase activity of the Salmonella type III secretion effector SlrP. Yeast two-hybrid identified SNRPD2 as a human binding partner of SlrP, and in vitro ubiquitination assays confirmed SNRPD2 is ubiquitinated by SlrP but not by related NEL-family E3 ligases SspH1 or SspH2. The specific lysine residues modified were identified by mass spectrometry. Yeast two-hybrid (binding), in vitro ubiquitination assay, mass spectrometry (lysine site identification) Biology Medium 36290420
2024 SNRPD2 (PD2) is the most highly upregulated Sm protein in hepatocellular carcinoma (HCC) and acts as an oncogene. Mechanistically, SNRPD2 cooperates with HNRNPL to modulate DDX39A intron retention, sustaining expression of a DDX39A short variant (39A_S). 39A_S mediates nuclear export of MYC mRNA to maintain high MYC protein expression, while MYC in turn potentiates SNRPD2 transcription, forming a positive feedback loop. The small molecule digitoxin can directly interact with SNRPD2 and suppresses HCC. Overexpression/knockdown functional assays, splicing analysis (intron retention), MYC mRNA nuclear export assays, drug binding (digitoxin-SNRPD2 interaction), in vivo tumor models Advanced science Medium 39018261
2024 SNRPD2 interacts with the glutamic-proline (EP) domain of PABPN1 and disrupts PABPN1 liquid-liquid phase separation (LLPS). This disruption of PABPN1 LLPS attenuates PABPN1's repression of proximal poly(A) sites, leading to shortened 3' UTR of CTNNBIP1 and promoting colorectal cancer cell proliferation and migration. Co-immunoprecipitation (SNRPD2-PABPN1 interaction), LLPS assay, APA profiling, domain mapping, functional proliferation/migration assays Science China. Life sciences Medium 38811444
2022 Free U1 snRNP proteins including SNRPD2 (when knocked down or overexpressed) promote usage of proximal alternative polyadenylation (APA) sites at the transcriptome level, contrary to the repressive effect of the intact U1 snRNP complex. This occurs through interaction with 3' end processing machinery. Knockdown and overexpression of SNRPD2 and other U1 snRNP proteins, transcriptome-wide APA profiling, phase transition assays, co-immunoprecipitation Journal of molecular cell biology Medium 36073763
2022 Silencing of SNRPD2 in HCC cell lines results in impaired proliferation and G1/M cell cycle arrest, accompanied by downregulation of transcription-cycle-related genes. siRNA knockdown of SNRPD2, cell proliferation assay, cell cycle analysis (FACS), gene expression analysis Diagnostics Low 35626291
2024 SNRPD2 silencing using shRNA-expressing lentiviral vectors selectively inhibits viability of cancer cell lines (including short-term cultured melanoma cells) but not normal cell cultures, establishing SNRPD2 as a cancer-selective lethal target. Genes with similar essentiality profiles implicate SNRPD2 in mRNA splicing, coordinated protein production, and mitosis. shRNA lentiviral knockdown, cell viability assays across cancer and normal cell lines, analysis of public cell viability datasets (DepMap), essentiality profile correlation International journal of molecular sciences Medium 39684842
2026 Mutant p53 (mtp53) physically binds SNRPD2 and cooperates with it to facilitate assembly of the Sm/SMN protein complex, an essential spliceosome component, thereby modulating alternative splicing of pre-mRNAs. Co-depletion of mtp53 and SNRPD2 reduces oncogenic OTUD3 transcripts and increases tumor-suppressor OTUD3 counterparts through an exon-skipping event. Co-immunoprecipitation (mtp53-SNRPD2 interaction), overexpression/depletion functional assays, alternative splicing analysis (exon skipping of OTUD3), in vivo xenograft models with engineered exosomes delivering siRNAs Advanced science Medium 41560375
2026 SNRPD2 knockdown induces retention of intron 5 in DDX39B pre-mRNA, producing a noncoding transcript degraded by nonsense-mediated decay (NMD), thereby reducing DDX39B expression. Reduced DDX39B levels permit activation of a cryptic exon (Exon 2_3) in CTSC mRNA, introducing premature termination codons and triggering additional NMD-mediated CTSC degradation. Antisense oligonucleotides (ASOs) targeting SNRPD2 reduce tumor growth in a patient-derived xenograft model, establishing the SNRPD2-DDX39B-CTSC regulatory axis. SNRPD2 knockdown, intron retention/splicing analysis, NMD pathway assays, cryptic exon analysis, ASO treatment, patient-derived xenograft (PDX) in vivo model Cell death & disease Medium 41720762
2026 SNRPD2 knockdown induces exon 4 skipping in CPSF7 pre-mRNA, disrupting the RNA recognition motif (RRM) domain essential for CPSF7-mediated pre-mRNA cleavage and polyadenylation, and introducing premature termination codons that trigger NMD-mediated CPSF7 degradation. CPSF7 in turn governs APA events controlling UBE2K transcript stability. This defines a SNRPD2-CPSF7-UBE2K axis linking alternative splicing to alternative polyadenylation in ovarian cancer. SNRPD2/CPSF7 knockdown, exon skipping analysis, NMD assays, APA profiling, functional proliferation/migration assays, PDX model with ASOs Oncogene Medium 42098443
2026 NKRF directly represses transcription of SNRPD2, thereby constraining stress granule formation and attenuating drug tolerance to Osimertinib. The E3 ubiquitin ligase TRIM26 interacts with NKRF and promotes its K48-linked ubiquitination at Lys411, leading to proteasomal degradation, which in turn sustains SNRPD2 expression and enhances stress granule assembly. Genetic depletion of TRIM26 restored NKRF stability, suppressed stress granule formation, and re-sensitized resistant tumors to Osimertinib. Co-immunoprecipitation (TRIM26-NKRF interaction), ubiquitination assays (K48-linkage, Lys411 site), transcriptional reporter assays, SNRPD2 knockdown/overexpression, stress granule imaging, in vivo xenograft models Cell death & disease Medium 42026030
1999 Sm-D2 (SNRPD2) is recognized by anti-Sm autoantibodies in systemic lupus erythematosus, but with distinct antibody recognition patterns from Sm-D1 and Sm-D3. Human and murine lupus sera showed two patterns: Sm-D1/D3 (predominant) or Sm-D1/D2/D3. None of the MRL-derived monoclonal anti-Sm antibodies reacted with Sm-D2. Immunization with isolated Sm-D (containing all three D antigens) from rabbit thymus produced autoantibody reactive only with Sm-D2, indicating distinct antigenic epitopes among the Sm-D family members. Protein immunoblot screening of human and murine sera, monoclonal antibody panel screening, immunization with isolated Sm-D antigen Clinical immunology Medium 10444365

Source papers

Stage 0 corpus · 28 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2020 The Predicted Key Molecules, Functions, and Pathways That Bridge Mild Cognitive Impairment (MCI) and Alzheimer's Disease (AD). Frontiers in neurology 66 32308643
2021 N6-methyladenosine (m6A) modification and its clinical relevance in cognitive dysfunctions. Aging 36 34461609
2021 Splicing factors control triple-negative breast cancer cell mitosis through SUN2 interaction and sororin intron retention. Journal of experimental & clinical cancer research : CR 35 33648524
2022 Computational identification of host genomic biomarkers highlighting their functions, pathways and regulators that influence SARS-CoV-2 infections and drug repurposing. Scientific reports 32 35277538
2022 A developmentally programmed splicing failure contributes to DNA damage response attenuation during mammalian zygotic genome activation. Science advances 22 35417229
2021 WGCNA-Based Identification of Hub Genes and Key Pathways Involved in Nonalcoholic Fatty Liver Disease. BioMed research international 22 34938809
2020 Proteomic Characterization of Proliferation Inhibition of Well-Differentiated Laryngeal Squamous Cell Carcinoma Cells Under Below-Background Radiation in a Deep Underground Environment. Frontiers in public health 18 33194991
2024 Intron Retention of DDX39A Driven by SNRPD2 is a Crucial Splicing Axis for Oncogenic MYC/Spliceosome Program in Hepatocellular Carcinoma. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 16 39018261
2021 Genetic expression and mutational profile analysis in different pathologic stages of hepatocellular carcinoma patients. BMC cancer 16 34238242
2024 Single-cell and transcriptomic analyses reveal the influence of diabetes on ovarian cancer. BMC genomics 15 38166541
2024 Disruption of PABPN1 phase separation by SNRPD2 drives colorectal cancer cell proliferation and migration through promoting alternative polyadenylation of CTNNBIP1. Science China. Life sciences 14 38811444
1999 Diverse antibody recognition patterns of the multiple Sm-D antigen polypeptides. Clinical immunology (Orlando, Fla.) 14 10444365
2022 U1 snRNP proteins promote proximal alternative polyadenylation sites by directly interacting with 3' end processing core factors. Journal of molecular cell biology 13 36073763
2023 Are Alzheimer's and coronary artery diseases genetically related to longevity? Frontiers in psychiatry 9 36684006
2022 U1RNP/lncRNA/Transcription Cycle Axis Promotes Tumorigenesis of Hepatocellular Carcinoma. Diagnostics (Basel, Switzerland) 7 35626291
2022 SNRPD2 Is a Novel Substrate for the Ubiquitin Ligase Activity of the Salmonella Type III Secretion Effector SlrP. Biology 6 36290420
2024 Evaluation of Spliceosome Protein SmD2 as a Potential Target for Cancer Therapy. International journal of molecular sciences 4 39684842
2023 Integrated single cell transcriptome sequencing analysis reveals species-specific genes and molecular pathways for pig spermiogenesis. Reproduction in domestic animals = Zuchthygiene 4 37874861
2022 Identification and Validation of Novel Potential Pathogenesis and Biomarkers to Predict the Neurological Outcome after Cardiac Arrest. Brain sciences 3 35884735
2024 Transcriptomic Alterations in Spliceosome Components in Advanced Heart Failure: Status of Cardiac-Specific Alternative Splicing Factors. International journal of molecular sciences 2 39273537
2022 Identification of Three Genes Associated with Metastasis in Melanoma and Construction of a Predictive Model: A Multiracial Identification. Journal of oncology 1 35637857
2026 Dual Targeting of Mutant p53 and SNRPD2 via Engineered Exosomes Modulates Alternative Splicing to Suppress Ovarian Cancer. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 0 41560375
2026 SNRPD2-mediated regulation of DDX39B splicing promotes endometrial cancer progression by suppressing the activation of CTSC cryptic exons. Cell death & disease 0 41720762
2026 SNRPD2-dependency Fuels an Oncogenic Alternative Splicing Repertoire Driving Disease Aggressiveness in Glioma. Cancer genomics & proteomics 0 41771572
2026 Integrated analysis uncovers KCMF1 genetic susceptibility and the SNRPD2 axis in renal cell carcinoma. International journal of medical sciences 0 41938511
2026 TRIM26-mediated NKRF degradation drives Osimertinib resistance through SNRPD2-dependent stress granule formation in lung adenocarcinoma. Cell death & disease 0 42026030
2026 SNRPD2-CPSF7-UBE2K axis drives ovarian cancer progression via alternative splicing-polyadenylation crosstalk. Oncogene 0 42098443
2026 Byakangelicin alleviates metabolic dysfunction-associated steatohepatitis by selective inhibition of a non-canonical MTORC1 signaling pathway. Autophagy 0 42152469

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