Affinage

NAF1

H/ACA ribonucleoprotein complex non-core subunit NAF1 · UniProt Q96HR8

Length
494 aa
Mass
53.7 kDa
Annotated
2026-06-10
25 papers in source corpus 4 papers cited in narrative 4 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 5/5 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

NAF1 is a nuclear assembly factor for box H/ACA ribonucleoproteins, required for the accumulation of all H/ACA snoRNAs and for the biogenesis of the H/ACA-class telomerase RNP (PMID:12515383). It binds RNA in vitro and directly contacts the core H/ACA proteins Cbf5p/dyskerin and Nhp2p, but is not a stable subunit of mature H/ACA snoRNPs, indicating a transient assembly-chaperone role; recruitment to nascent transcripts occurs through its interaction with the phosphorylated CTD of RNA polymerase II, coupling H/ACA RNP assembly to transcription (PMID:12515383). NAF1 acts downstream of SHQ1 in a sequential, mutually exclusive assembly pathway: SHQ1 first binds dyskerin in a manner that precludes NAF1 and the other core proteins, so SHQ1 must release dyskerin before NAF1-dependent assembly can proceed (PMID:19383767). In humans, loss-of-function frameshift mutations in NAF1 cause telomere-mediated pulmonary fibrosis-emphysema; the truncated protein lacks a conserved C-terminal motif required for nuclear localization, and NAF1 haploinsufficiency selectively reduces telomerase RNA levels and telomere length while sparing rRNA pseudouridylation (PMID:27510903). Beyond its H/ACA role, NAF1 promotes 40S ribosomal subunit assembly and protein synthesis, and its depletion triggers ribosome stress with p53 reactivation (PMID:30936423).

Mechanistic history

Synthesis pass · year-by-year structured walk · 4 steps
  1. 2002 High

    Established NAF1 as the founding H/ACA snoRNP assembly factor and defined how it is recruited and what it binds, answering how H/ACA RNPs are assembled co-transcriptionally.

    Evidence Genetic depletion in yeast, in vitro RNA binding, two-hybrid and co-precipitation showing direct binding to Cbf5p, Nhp2p and the phosphorylated Pol II CTD

    PMID:12515383

    Open questions at the time
    • No structural model of the NAF1–core protein contacts
    • Mechanism of NAF1 release/exchange from the assembling RNP not defined
    • Direct demonstration that CTD binding drives recruitment in vivo not shown
  2. 2009 High

    Ordered the assembly pathway by showing SHQ1 acts upstream of NAF1 through mutually exclusive binding to dyskerin, establishing a sequential hand-off model for H/ACA RNP biogenesis.

    Evidence Human in vivo and in vitro binding assays, reconstituted NAF1-dependent H/ACA RNP assembly system, siRNA knockdown of SHQ1

    PMID:19383767

    Open questions at the time
    • Trigger that releases dyskerin from SHQ1 to permit NAF1 loading not identified
    • Stoichiometry and timing of the NAF1-to-core-protein transition unresolved
  3. 2016 High

    Connected NAF1 to human disease and defined the C-terminal nuclear-localization motif, showing haploinsufficiency selectively limits telomerase RNA and telomere length.

    Evidence Patient mutation analysis, CRISPR/Cas9 editing in cells and mice, telomerase RNA quantification, pseudouridylation assay, C-terminal deletion localization

    PMID:27510903

    Open questions at the time
    • Why telomerase RNA is more dosage-sensitive than other H/ACA RNAs not mechanistically explained
    • Identity of the C-terminal nuclear-targeting determinant/partner not defined
  4. 2019 Medium

    Extended NAF1 function beyond H/ACA assembly to 40S subunit biogenesis and protein synthesis, linking its loss to ribosome stress and p53 activation in cancer cells.

    Evidence shRNA knockdown in glioma cells, ribosome assembly and protein synthesis assays, xenografts, transcriptional regulation and p53/MDM2 pathway analysis

    PMID:30936423

    Open questions at the time
    • Single-lab study; direct molecular role of NAF1 in 40S assembly not biochemically reconstituted
    • Whether 40S effect is separable from H/ACA snoRNP assembly function unclear
    • Transcriptional feedback loops (c-Myc, NRF2, TERT) inferred from implied ChIP/reporter, not fully detailed

Open questions

Synthesis pass · forward-looking unresolved questions
  • How NAF1 mechanistically distinguishes telomerase RNP assembly from other H/ACA RNPs, and how its assembly-factor role relates to its reported role in 40S biogenesis, remains unresolved.
  • No structural basis for substrate selectivity among H/ACA RNAs
  • No reconstitution linking NAF1 directly to 40S subunit assembly

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0098772 molecular function regulator activity 2 GO:0003723 RNA binding 1
Localization
GO:0005634 nucleus 2
Pathway
R-HSA-8953854 Metabolism of RNA 2 R-HSA-1643685 Disease 1
Partners
CBF5/DYSKERINNHP2RNA POLYMERASE II CTDSHQ1
Complex memberships
box H/ACA snoRNP (transient assembly intermediate)telomerase RNP (assembly intermediate)

Evidence

Reading pass · 4 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2002 Yeast Naf1p is required for accumulation of all box H/ACA snoRNAs and functions as an H/ACA snoRNP assembly factor. Naf1p is localized to the nucleus, is not a stable component of mature H/ACA snoRNPs, shows in vitro RNA-binding activity, and directly binds the core H/ACA proteins Cbf5p and Nhp2p. Naf1p also binds the phosphorylated CTD of RNA polymerase II in vivo (two-hybrid) and in cell lysates, suggesting it is recruited to the CTD to promote co-transcriptional snoRNP assembly. Genetic depletion in yeast, in vitro RNA-binding assay, two-hybrid and co-precipitation with CTD, direct binding to Cbf5p and Nhp2p RNA (New York, N.Y.) High 12515383
2009 Human SHQ1 and NAF1 act sequentially in H/ACA RNP assembly: SHQ1 binds the core pseudouridine synthase NAP57/dyskerin both in vivo and in vitro, and this interaction precludes binding of NAF1 and other H/ACA core proteins. SHQ1 therefore acts upstream of NAF1. In an in vitro H/ACA RNP assembly system dependent on NAF1, excess recombinant SHQ1 interferes with assembly. Knockdown of SHQ1 prevents accumulation of newly synthesized H/ACA reporter RNA and reduces endogenous H/ACA RNA levels including telomerase RNA. Co-IP in vivo and in vitro binding assays, in vitro H/ACA RNP assembly system, siRNA knockdown, subcellular localization (SHQ1 excluded from Cajal bodies/nucleoli) RNA (New York, N.Y.) High 19383767
2016 Loss-of-function frameshift mutations in human NAF1 (nuclear assembly factor 1) cause pulmonary fibrosis-emphysema. A truncated NAF1 lacking the conserved C-terminal motif was detected in patient cells; this C-terminal motif is required for nuclear localization of NAF1. Introduction of the frameshift mutation by CRISPR/Cas9 genome editing reduced telomerase RNA levels. Naf1(+/-) mice generated by CRISPR/Cas9 had half the normal levels of telomerase RNA; other H/ACA RNA levels were also decreased, but rRNA pseudouridylation was intact and no ribosomal pathology was found in first-generation heterozygotes. Disease in mutation carriers is telomere-mediated, with NAF1 haploinsufficiency selectively disturbing telomere length homeostasis by decreasing telomerase RNA. Patient mutation analysis, CRISPR/Cas9 genome editing (cell lines and mice), telomerase RNA quantification, pseudouridylation assay, direct nuclear localization experiment with C-terminal deletion Science translational medicine High 27510903
2019 NAF1 (nuclear assembly factor 1) promotes 40S ribosomal subunit assembly and protein synthesis in glioma cells. NAF1 depletion triggers ribosome stress, impairs ribosomal biosynthesis, and reactivates p53 signaling by blocking MDM2. NAF1 transcription is regulated by c-Myc, NRF2, and TERT, forming positive feedback loops. NAF1 knockdown reduced cell growth in vitro and in vivo. shRNA knockdown, ribosome assembly assays, protein synthesis measurements, in vivo xenograft, transcriptional regulation analysis (c-Myc, NRF2, TERT ChIP/reporter implied), p53/MDM2 pathway analysis Oncogenesis Medium 30936423

Source papers

Stage 0 corpus · 25 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2009 Antagonism of Beclin 1-dependent autophagy by BCL-2 at the endoplasmic reticulum requires NAF-1. The EMBO journal 225 20010695
2013 NAF-1 and mitoNEET are central to human breast cancer proliferation by maintaining mitochondrial homeostasis and promoting tumor growth. Proceedings of the National Academy of Sciences of the United States of America 172 23959881
2016 Loss-of-function mutations in the RNA biogenesis factor NAF1 predispose to pulmonary fibrosis-emphysema. Science translational medicine 171 27510903
2009 SHQ1 is required prior to NAF1 for assembly of H/ACA small nucleolar and telomerase RNPs. RNA (New York, N.Y.) 96 19383767
2012 Bcl-2-associated autophagy regulator Naf-1 required for maintenance of skeletal muscle. Human molecular genetics 91 22343142
2002 Naf1 p is a box H/ACA snoRNP assembly factor. RNA (New York, N.Y.) 68 12515383
2018 Resveratrol-Induced Downregulation of NAF-1 Enhances the Sensitivity of Pancreatic Cancer Cells to Gemcitabine via the ROS/Nrf2 Signaling Pathways. Oxidative medicine and cellular longevity 66 29765509
2015 The Fe-S cluster-containing NEET proteins mitoNEET and NAF-1 as chemotherapeutic targets in breast cancer. Proceedings of the National Academy of Sciences of the United States of America 65 25762074
1999 Identification and cloning of a novel cellular protein Naf1, Nef-associated factor 1, that increases cell surface CD4 expression. FEBS letters 53 9923610
2014 Integrated strategy reveals the protein interface between cancer targets Bcl-2 and NAF-1. Proceedings of the National Academy of Sciences of the United States of America 52 24706857
2003 Identification of Naf1/ABIN-1 among TNF-alpha-induced expressed genes in human synoviocytes using oligonucleotide microarrays. FEBS letters 43 12965196
2013 Nutrient-deprivation autophagy factor-1 (NAF-1): biochemical properties of a novel cellular target for anti-diabetic drugs. PloS one 41 23717386
2017 Interactions between mitoNEET and NAF-1 in cells. PloS one 40 28426722
2020 NAF-1 Inhibition by Resveratrol Suppresses Cancer Stem Cell-Like Properties and the Invasion of Pancreatic Cancer. Frontiers in oncology 38 32766132
2002 A new ERK2 binding protein, Naf1, attenuates the EGF/ERK2 nuclear signaling. Biochemical and biophysical research communications 32 12220502
2014 A point mutation in the [2Fe-2S] cluster binding region of the NAF-1 protein (H114C) dramatically hinders the cluster donor properties. Acta crystallographica. Section D, Biological crystallography 28 24914968
2003 High frequency of alternative splicing of human genes participating in the HIV-1 life cycle: a model using TSG101, betaTrCP, PPIA, INI1, NAF1, and PML. Journal of acquired immune deficiency syndromes (1999) 17 14526201
2015 NAF-1 antagonizes starvation-induced autophagy through AMPK signaling pathway in cardiomyocytes. Cell biology international 13 25689847
2006 Multiple splicing variants of Naf1/ABIN-1 transcripts and their alterations in hematopoietic tumors. International journal of molecular medicine 13 17016622
2018 The anti-apoptotic proteins NAF-1 and iASPP interact to drive apoptosis in cancer cells. Chemical science 12 30774867
2019 Increased expression of NAF1 contributes to malignant phenotypes of glioma cells through promoting protein synthesis and associates with poor patient survival. Oncogenesis 9 30936423
2020 NAF1 rs4691896 Is Significantly Associated with Coal Workers' Pneumoconiosis in a Chinese Han Population: A Case-Control Study. Medical science monitor : international medical journal of experimental and clinical research 5 32333749
2022 Colorectal cancer-associated SNP rs17042479 is involved in the regulation of NAF1 promoter activity. PloS one 3 36067202
2025 Host factor Naf1 restricts HIV-1 infection of myeloid cells and compromises the capacity of dendritic cell to prime CD4+ T cell. Virologica Sinica 1 40139499
2005 Production and characterization of a monoclonal antibody specific to Nef-associated factor 1 (Naf1)/A20-binding inhibitor of NF-kappaB activation (ABIN-1). Hybridoma (2005) 0 16225425

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