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Showing NUFIP1RSA1 is a alias.

NUFIP1

FMR1-interacting protein NUFIP1 · UniProt Q9UHK0

Length
495 aa
Mass
56.3 kDa
Annotated
2026-06-10
19 papers in source corpus 9 papers cited in narrative 9 extracted findings
Cross-family judge faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

NUFIP1 is a nucleocytoplasmic shuttling protein that couples ribosome metabolism to selective autophagy and RNA biogenesis (PMID:12941608, PMID:29700228). It localizes to RNA-containing nuclear matrix structures and to cytoplasmic and ribosome-associated pools, shuttling between compartments through a CRM1-dependent nuclear export signal (PMID:12941608). In the nucleus it functions as a scaffold/assembly factor for box C/D snoRNPs by directly binding the RNA-binding core protein 15.5K (Snu13p), an interaction defined at residue resolution and predicted to keep snoRNPs in an inactive pre-assembly state; ZNHIT3 (Hit1p homolog) stabilizes NUFIP1 and the resulting heterotrimer engages C/D snoRNAs and the core protein Nop58 (PMID:24234454, PMID:25170085). NUFIP1 also stimulates RNA polymerase II transcription, acting with BRCA1 and the P-TEFb subunit Cyclin T1 and requiring an intact zinc-finger domain (PMID:15107825). Its best-characterized role is as a selective autophagy (ribophagy) receptor: upon mTORC1 inhibition or nutrient starvation it relocalizes from the nucleus to autophagosomes and lysosomes and directly binds LC3B to deliver ribosomes for degradation, promoting cell survival (PMID:29700228). This ribophagy activity is exploited in physiological and disease contexts, supporting nucleoside secretion by cancer-associated fibroblasts to fuel pancreatic tumor growth (PMID:35982178) and suppressing cGAS-STING- and ZBP1-driven PANoptosis in CD4+ T cells during sepsis (PMID:40995563). In a distinct branch, phosphorylated NUFIP1 binds RPA32 under amino acid deprivation to recruit the ATR-ATRIP complex and trigger the DNA damage response, protecting against necroptotic enteritis in vivo (PMID:39753713).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2003 Medium

    Established that NUFIP1 is not a static nuclear protein but actively shuttles between nucleus and cytoplasm and associates with ribosomes, foreshadowing its later dual nuclear/cytoplasmic roles.

    Evidence Subcellular fractionation, immunofluorescence, synaptosome isolation, and leptomycin B inhibition of CRM1-dependent export

    PMID:12941608

    Open questions at the time
    • Did not define the cargo or function of cytoplasmic ribosome association
    • Single lab; export signal mapped functionally but not structurally
  2. 2004 Medium

    Identified a nuclear transcriptional role, placing NUFIP1 in complexes with BRCA1 and P-TEFb/Cyclin T1 and showing it is required to stimulate RNA polymerase II transcription via its zinc finger.

    Evidence Yeast two-hybrid, immunodepletion plus in vitro transcription, Co-IP, zinc-finger mutagenesis, reporter assays in 293 cells

    PMID:15107825

    Open questions at the time
    • Mechanism by which NUFIP1 dissociates hyperphosphorylated pol II not structurally resolved
    • Functional link between BRCA1 and Cyclin T1 binding not established
    • Single lab
  3. 2013 High

    Defined NUFIP1 (Rsa1p homolog) as a box C/D snoRNP assembly scaffold, mapping its direct interface with the 15.5K/Snu13p core protein and proposing it blocks premature snoRNP activity.

    Evidence NMR structure determination, biophysical binding assays, site-directed mutagenesis with snoRNP formation readouts in yeast, docking

    PMID:24234454

    Open questions at the time
    • Structural work performed on yeast Rsa1p, not human NUFIP1
    • How assembly is coupled to release of the inactive complex not shown
  4. 2014 High

    Extended the snoRNP assembly model by showing ZNHIT3 stabilizes NUFIP1 and that a Snu13p-Rsa1p-Hit1p heterotrimer engages C/D snoRNAs and Nop58.

    Evidence Pulldown/MS, NMR structure of yeast Rsa1p-Hit1p, reconstituted heterotrimer binding, snoRNA stability assays, ZNHIT3 regulation of human NUFIP1 abundance

    PMID:25170085

    Open questions at the time
    • Most structural/functional data in yeast; human heterotrimer not reconstituted
    • Order of assembly events with Nop58 incompletely defined
  5. 2018 High

    Defined NUFIP1's signature function as a starvation- and mTORC1-regulated ribophagy receptor that binds LC3B to deliver ribosomes to autophagosomes and supports cell survival.

    Evidence Quantitative lysosome proteomics, NUFIP1-LC3B Co-IP, imaging/fractionation, knockdown with survival readout, mTORC1 inhibition

    PMID:29700228

    Open questions at the time
    • How nuclear NUFIP1 is mobilized to autophagosomes mechanistically unresolved
    • Selectivity determinants for ribosome cargo not fully defined
  6. 2019 Medium

    Showed NUFIP1-LC3 engagement is context-dependent, occurring under mechanical stress in trabecular meshwork cells without triggering ribophagy, implying a broader selective-autophagy receptor capacity.

    Evidence Co-IP, biochemical fractionation, immunofluorescence, GFP-LC3 expression, leptomycin B treatment

    PMID:31476975

    Open questions at the time
    • The non-ribosomal autophagy target was not identified
    • Single cell type and lab
  7. 2022 Medium

    Connected NUFIP1-dependent ribophagy to tumor metabolism, showing it drives nucleoside secretion by cancer-associated fibroblasts that fuels pancreatic tumor growth.

    Evidence NUFIP1 knockdown/inhibition in CAFs, orthotopic PDAC model, nucleoside metabolite measurement, MYC-dependence analysis

    PMID:35982178

    Open questions at the time
    • Direct link between ribophagy flux and nucleoside output not biochemically traced
    • Single lab
  8. 2025 Medium

    Revealed a phosphorylation-dependent DNA damage response role in which NUFIP1 binds RPA32 to recruit ATR-ATRIP under amino acid deprivation, protecting intestinal tissue from necroptotic inflammation.

    Evidence Phospho-NUFIP1 Co-IP with RPA32/ATR-ATRIP, conditional knockout mice, non-phosphorylatable mutant rescue, in vitro DDR assays

    PMID:39753713

    Open questions at the time
    • Kinase responsible for NUFIP1 phosphorylation not identified
    • Relationship between this DDR role and ribophagy unresolved
    • Single lab
  9. 2025 Medium

    Linked NUFIP1 ribophagy to innate immune cell death control, showing ribosome collision recruits NUFIP1 to STING and that NUFIP1-mediated ribophagy suppresses ZBP1-driven PANoptosis in CD4+ T cells in sepsis.

    Evidence TMT proteomics, NUFIP1-STING Co-IP, knockdown in Jurkat cells, cecal ligation/puncture model, clinical CD4+ T cell analysis

    PMID:40995563

    Open questions at the time
    • Mechanism coupling ribosome collision to NUFIP1 recruitment not defined
    • Direct interaction vs indirect STING association not fully distinguished
    • Single lab

Open questions

Synthesis pass · forward-looking unresolved questions
  • How NUFIP1's distinct activities — nuclear snoRNP assembly and transcription, cytoplasmic ribophagy, and phospho-dependent DDR signaling — are coordinated and switched in response to nutrient and stress cues remains unknown.
  • No unified regulatory model linking nuclear and autophagy functions
  • Human structural data for the LC3B and RPA32 interactions lacking
  • Switch from snoRNP/transcription roles to ribophagy receptor not mechanistically explained

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 3 GO:0003723 RNA binding 2 GO:0140110 transcription regulator activity 1
Localization
GO:0005634 nucleus 2 GO:0005730 nucleolus 2 GO:0005764 lysosome 2 GO:0005829 cytosol 1 GO:0005840 ribosome 1
Pathway
R-HSA-9612973 Autophagy 4 R-HSA-8953854 Metabolism of RNA 2 R-HSA-73894 DNA Repair 1 R-HSA-74160 Gene expression (Transcription) 1
Complex memberships
P-TEFbbox C/D snoRNP assembly complex (Snu13p/15.5K-Rsa1p/NUFIP1-Hit1p/ZNHIT3)

Evidence

Reading pass · 9 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2018 Upon mTORC1 inhibition or nutrient starvation, NUFIP1 redistributes from the nucleus to autophagosomes and lysosomes, where it directly binds LC3B to deliver ribosomes to autophagosomes, functioning as a selective autophagy receptor (ribophagy receptor). This starvation-induced ribophagy depends on the capacity of NUFIP1 to bind LC3B and promotes cell survival. Quantitative lysosome proteomics, co-immunoprecipitation (NUFIP1-LC3B interaction), subcellular fractionation/imaging, loss-of-function (NUFIP1 knockdown with cell survival readout), mTORC1 inhibition experiments Science High 29700228
2003 NUFIP1 is a nucleocytoplasmic shuttling protein: it localizes in the nuclear matrix in RNA-containing structures, is also present in the cytoplasm associated with ribosomes, and is detected in functional synaptoneurosomes in neurons where it co-localizes with ribosomes. NUFIP1 contains a functional CRM1-dependent nuclear export signal mediating its shuttling between nucleus and cytoplasm. Subcellular fractionation, immunofluorescence imaging, synaptosome isolation and immunodetection, leptomycin B (CRM1 inhibitor) treatment demonstrating nuclear export signal function Experimental cell research Medium 12941608
2013 NUFIP1 (the human homolog of yeast Rsa1p) acts as a scaffold/assembly factor for box C/D snoRNPs by directly interacting with the RNA-binding core protein 15.5K (human homolog of yeast Snu13p). NMR structure determination and docking identified the interface: residues R249, R246, K250 of Rsa1p and E72, D73 of Snu13p form electrostatic interactions, with W253 of Rsa1p inserted in a hydrophobic cavity of Snu13p. This interaction is predicted to be exclusive of interactions in active snoRNPs, suggesting Rsa1p/NUFIP1 prevents premature snoRNP activity. NMR structure determination, biophysical interaction assays, site-directed mutagenesis in yeast (cell growth and snoRNP formation readouts), molecular docking Nucleic acids research High 24234454
2014 NUFIP1 (human functional homolog of yeast Rsa1p) interacts with ZNHIT3 (TRIP3, human homolog of yeast Hit1p), which stabilizes NUFIP1 protein levels. The yeast Rsa1p-Hit1p complex structure was determined by NMR, revealing a novel mode of protein-protein association. The purified Snu13p-Rsa1p-Hit1p heterotrimer can interact with C/D snoRNAs and core protein Nop58, placing NUFIP1 within the snoRNP assembly pathway. Proteomic (pulldown/MS), NMR structure determination of yeast Rsa1p-Hit1p complex, functional studies (C/D snoRNA stability, pre-RNA maturation), in vitro binding with purified heterotrimer, demonstration that human ZNHIT3 regulates NUFIP1 abundance Nucleic acids research High 25170085
2004 NUFIP (NUFIP1) interacts with BRCA1 (identified by yeast two-hybrid) and with the P-TEFb complex via its Cyclin T1 subunit. NUFIP stimulates activator-independent RNA polymerase II transcription in vitro and in vivo; immunodepletion of endogenous NUFIP markedly decreases pol II transcription. NUFIP associates with preinitiation, open, and elongation complexes, and facilitates ATP-dependent dissociation of hyperphosphorylated pol II from open transcription complexes in vitro. Mutation of the zinc-finger domain abolishes NUFIP-mediated transcriptional activation. Yeast two-hybrid, immunodepletion + in vitro transcription assay, co-immunoprecipitation, in vitro transcription reconstitution, zinc-finger domain mutagenesis, in vivo reporter assay in 293 cells Oncogene Medium 15107825
2019 Under cyclic mechanical stress (CMS) in trabecular meshwork cells, nuclear LC3 co-immunoprecipitates with NUFIP1 in the nucleolus. NUFIP1 translocates from the nucleus to LAMP2-positive (lysosomal) organelles in mechanically stretched cells, but without triggering ribophagy, suggesting a more general role of NUFIP1 as a selective autophagy receptor for a target other than ribosomes under mechanical stress. Co-immunoprecipitation, biochemical fractionation, immunofluorescence imaging, adenoviral GFP-LC3 expression, leptomycin B treatment Autophagy Medium 31476975
2025 Under amino acid deficiency, phosphorylated NUFIP1 binds replication protein A2 (RPA32) to recruit the ATR-ATRIP complex, triggering the DNA damage response (DDR). Loss of NUFIP1 impairs the DDR and induces necroptosis-related spontaneous enteritis in vivo; reintroduction of NUFIP1 but not its non-phosphorylatable mutant rescues bowel inflammation in conditional knockout mice. Co-immunoprecipitation (phospho-NUFIP1 with RPA32/ATR-ATRIP), conditional knockout mouse model, non-phospho-mutant rescue experiments, in vitro cell DDR assays Nature metabolism Medium 39753713
2025 In sepsis, ribosome collision activates the cGAS-STING signaling axis, which recruits NUFIP1 to STING protein complexes. NUFIP1-mediated ribophagy suppresses ZBP1-mediated PANoptosome formation and PANoptosis in CD4+ T lymphocytes; NUFIP1 knockdown exacerbates PANoptosis and impairs T cell function (cytokine production, proliferation). Tandem mass tagging (TMT) proteomics, Co-IP (NUFIP1-STING interaction), NUFIP1 knockdown in Jurkat T cells, cecal ligation and puncture sepsis mouse model, clinical CD4+ T cell analysis Research (Washington, D.C.) Medium 40995563
2022 In cancer-associated fibroblasts (CAFs), NUFIP1-dependent autophagy (ribophagy) mediates secretion of nucleosides that support pancreatic tumor growth and glucose utilization under glutamine deprivation. Inhibiting nucleoside secretion by targeting NUFIP1 in stromal cells reduced tumor weight in an orthotopic mouse model. NUFIP1 knockdown/inhibition in CAFs, orthotopic PDAC mouse model, metabolite (nucleoside) measurement, MYC-dependence analysis Nature cancer Medium 35982178

Source papers

Stage 0 corpus · 19 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2018 NUFIP1 is a ribosome receptor for starvation-induced ribophagy. Science (New York, N.Y.) 292 29700228
2022 Cancer-associated fibroblasts employ NUFIP1-dependent autophagy to secrete nucleosides and support pancreatic tumor growth. Nature cancer 76 35982178
2019 The autophagic protein LC3 translocates to the nucleus and localizes in the nucleolus associated to NUFIP1 in response to cyclic mechanical stress. Autophagy 56 31476975
2003 NUFIP1 (nuclear FMRP interacting protein 1) is a nucleocytoplasmic shuttling protein associated with active synaptoneurosomes. Experimental cell research 47 12941608
2014 Protein Hit1, a novel box C/D snoRNP assembly factor, controls cellular concentration of the scaffolding protein Rsa1 by direct interaction. Nucleic acids research 44 25170085
2013 Characterization of the interaction between protein Snu13p/15.5K and the Rsa1p/NUFIP factor and demonstration of its functional importance for snoRNP assembly. Nucleic acids research 34 24234454
1985 Rsa1 polymorphism at the insulin receptor locus (INSR) on chromosome 19. Nucleic acids research 33 3001646
2019 Thrombolytic Potential of Novel Thiol-Dependent Fibrinolytic Protease from Bacillus cereus RSA1. Biomolecules 27 31861284
2004 BRCA1 cooperates with NUFIP and P-TEFb to activate transcription by RNA polymerase II. Oncogene 26 15107825
1982 Purification of rabbit sperm autoantigens by preparative SDS gel electrophoresis: amino acid and carbohydrate content of RSA-1. Biology of reproduction 26 7139016
2025 NUFIP1 integrates amino acid sensing and DNA damage response to maintain the intestinal homeostasis. Nature metabolism 15 39753713
2021 Computational-approach understanding the structure-function prophecy of Fibrinolytic Protease RFEA1 from Bacillus cereus RSA1. PeerJ 14 34141495
2025 NUFIP1-Mediated Ribophagy Alleviates PANoptosis of CD4+ T Lymphocytes in Sepsis via the cGAS-STING Pathway. Research (Washington, D.C.) 13 40995563
2024 NUFIP1-engineered exosomes derived from hUMSCs regulate apoptosis and neurological injury induced by propofol in newborn rats. Neurotoxicology 5 38599287
2021 Targeting NUFIP1 Suppresses Growth and Induces Senescence of Colorectal Cancer Cells. Frontiers in oncology 4 34367967
2021 High Resolution Structure of the Mature Capsid of Ralstonia solanacearum Bacteriophage ϕRSA1 by Cryo-Electron Microscopy. International journal of molecular sciences 3 34681713
2026 Erratum to "NUFIP1-Mediated Ribophagy Alleviates PANoptosis of CD4+ T Lymphocytes in Sepsis via the cGAS-STING Pathway". Research (Washington, D.C.) 0 41783044
2026 NUFIP1-engineered exosomes modulate propofol-induced neurotoxicity in neonatal rats via the ERS apoptotic pathway. Apoptosis : an international journal on programmed cell death 0 41942784
2025 NUFIP1 at the crossroads of ribophagy and disease: unveiling therapeutic implications. Journal of translational medicine 0 41366789

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