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this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.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 literature gathered here consistently studies FBXO16 (F-box only protein 16) as an F-box domain–containing substrate-receptor component of CRL1/SCF (CUL1–SKP1–RBX1) ubiquitin ligase complexes, matching the target identity and domain logic in UniProt (F-box domain(s) plus additional C-terminal substrate-recognition region). No evidence reviewed corresponded to a different gene with a confusingly similar symbol. (ji2021fbxo16mediatedhnrnplubiquitination pages 1-2, ji2021fbxo16mediatedhnrnplubiquitination pages 6-8, ji2021fbxo16mediatedhnrnplubiquitination pages 4-6)
F-box proteins are generally understood to function as substrate-recognition receptors in SCF/CRL1 E3 ubiquitin ligase complexes, where the F-box motif mediates association with SKP1, and the cullin scaffold (CUL1) with RBX1 recruits an E2 enzyme to catalyze ubiquitin transfer to substrates. FBXO16 behaves consistently with this architecture: its F-box domain is required for assembling functional ubiquitin-ligase activity, whereas a C-terminal region mediates substrate binding/recognition. (ji2021fbxo16mediatedhnrnplubiquitination pages 6-8, ji2021fbxo16mediatedhnrnplubiquitination pages 4-6, khan2019attenuationoftumor pages 4-6, sugimotoishige2025fbxo16mediatesdegradation pages 8-9)
For FBXO16, the “primary function” is not to catalyze a chemical reaction like an enzyme active site; rather, it confers substrate specificity on a ubiquitin ligase complex by binding selected proteins and positioning them for polyubiquitination and usually proteasomal degradation (often via K48-linked polyubiquitin). (khan2019attenuationoftumor pages 4-6, zhang2024mir937amplificationpotentiates pages 7-10, ji2021fbxo16mediatedhnrnplubiquitination pages 8-9)
Across primary mechanistic studies, FBXO16 has been experimentally validated to target multiple proteins for ubiquitin-dependent degradation:
Two consistent structure–function principles emerge:
Khan et al. provide direct figure-level evidence supporting: (i) FBXO16–β-catenin interaction, (ii) increased total and K48-linked ubiquitination of nuclear β-catenin with FBXO16 expression, and (iii) domain mapping showing the C-terminus is essential for β-catenin interaction. (khan2019attenuationoftumor media a83ab1b6)
FBXO16 functional evidence strongly emphasizes nuclear contexts:
Taken together, FBXO16 appears to be a nuclear-relevant CRL1 substrate receptor with substrate-dependent localization (and some evidence for both cytoplasmic and nuclear presence in the NF-κB study’s discussion referencing HPA). (sugimotoishige2025fbxo16mediatesdegradation pages 7-8)
FBXO16 suppresses Wnt signaling by promoting nuclear β-catenin degradation. In glioblastoma models, this is linked to reduced expression of canonical β-catenin/TCF outputs such as c-Myc and Cyclin D1, reduced TOPFlash reporter activity, and reduced malignant phenotypes. (khan2019attenuationoftumor pages 4-6, khan2019attenuationoftumor pages 1-2)
In ovarian cancer models, FBXO16-mediated hnRNPL degradation is associated with suppression of malignant phenotypes and reduction of multiple oncogenic signaling outputs. In FBXO16 KO conditions, hnRNPL knockdown was sufficient to reverse activation of MAPK, RAS, and Wnt signaling described in that study. (ji2021fbxo16mediatedhnrnplubiquitination pages 8-9)
A 2024 study identifies ULK1 as a degradation substrate of FBXO16 and links FBXO16 to autophagy suppression: FBXO16 overexpression reduces ULK1 and shifts autophagy markers (e.g., lower LC3II/I ratio, increased p62), while FBXO16 knockdown increases ULK1 protein. (zhang2024mir937amplificationpotentiates pages 7-10)
In dendritic cell contexts, Fbxo16 functions as a substrate receptor for p65 in a PDLIM2-containing CRL1 complex; Fbxo16 promotes p65 degradation and thereby limits NF-κB transactivation and pro-inflammatory cytokine expression (e.g., IL-6). (sugimotoishige2025fbxo16mediatesdegradation pages 6-7, sugimotoishige2025fbxo16mediatesdegradation pages 8-9)
Zhang et al. (published Oct 2024 in Cell Death & Disease) propose and experimentally support a regulatory axis where MIR937 amplification increases miR-937-5p, which targets the 3′ UTR of FBXO16, reducing FBXO16 levels and thereby restricting FBXO16’s degradative effect on ULK1, promoting autophagy and proliferative capacity in high-grade serous ovarian cancer models. (zhang2024mir937amplificationpotentiates pages 7-10)
Open Targets aggregates genetic/literature evidence linking FBXO16 to neoplasm-related terms and specific cancers (e.g., ovarian cancer, glioblastoma multiforme) and also reports associations for amyotrophic lateral sclerosis (ALS) in its evidence set. While these are not mechanistic proofs, they are useful for prioritizing disease contexts for follow-up experimentation. (OpenTargets Search: -FBXO16)
Primary mechanistic studies support FBXO16 as a tumor-suppressive regulator through degradation of oncogenic effectors (β-catenin, hnRNPL, ULK1-mediated autophagy), suggesting potential translational applications:
The 2024 MIR937/miR-937-5p → FBXO16 → ULK1 axis provides a concrete example of a potentially druggable regulatory layer: blocking miR-937-5p or restoring FBXO16 could reduce ULK1-mediated autophagy that supports tumor cell fitness. (zhang2024mir937amplificationpotentiates pages 7-10)
The strongest, repeatedly supported functional annotation is:
FBXO16 is a CRL1/SCF substrate-recognition protein that drives K48-linked polyubiquitination and proteasomal degradation of select substrates, with prominent nuclear activity.
This is supported by multiple primary mechanistic datasets across different substrates and contexts (β-catenin, hnRNPL, ULK1; nuclear p65 in immune context). (khan2019attenuationoftumor pages 4-6, ji2021fbxo16mediatedhnrnplubiquitination pages 8-9, zhang2024mir937amplificationpotentiates pages 7-10, sugimotoishige2025fbxo16mediatesdegradation pages 8-9)
FBXO16 substrates appear context-dependent (tumor type, cell state, and possibly binding partners like PDLIM2). For example, ULK1 is prominent in one ovarian cancer mechanism, while hnRNPL is emphasized in another; the ULK1-focused study notes hnRNPL is not altered in that specific context, implying separable substrate modules. (zhang2024mir937amplificationpotentiates pages 7-10)
Independent substrate-mapping experiments converge on the FBXO16 C-terminus as a key substrate-binding interface (β-catenin, hnRNPL; likely ULK1). This suggests that perturbations in the C-terminal region (mutation, truncation, binding competition) could broadly disable FBXO16 substrate recognition even if SCF assembly remains intact. (khan2019attenuationoftumor pages 4-6, ji2021fbxo16mediatedhnrnplubiquitination pages 8-9)
The following table consolidates substrates, mechanisms, domains, localization, contexts, and key quantitative points.
| Substrate/Interactor | Evidence type (co-IP, ubiquitination, degradation, functional assay) | Ubiquitin linkage / degradation mechanism | Required FBXO16 domain(s) | Cellular compartment | Biological context (cell type/cancer) | Key quantitative data (n, fold-changes, p-values) | Publication (authors, journal, year, date) | URL | Citation context ID |
|---|---|---|---|---|---|---|---|---|---|
| β-catenin (CTNNB1) | IP/co-IP interaction in RANG-2 and LN229; nuclear-fraction ubiquitination assays; MG132 rescue; TOPFlash Wnt reporter; migration/proliferation/xenograft assays | K48-linked polyubiquitination of nuclear β-catenin followed by proteasome-dependent degradation; reported GSK3β-independent | C-terminal region required for β-catenin interaction; ΔC loses binding, while ΔF and N-terminal deletion retain interaction | Predominantly nuclear β-catenin pool | Human glioblastoma models (RANG-2, LN229; xenografts) | ~4-fold reduction in nuclear RFP-β-catenin speckles with FBXO16 overexpression; ~30% reduced migration (P≤0.008); decreased TOPFlash, c-Myc, Cyclin D1; qRT-PCR cohort glioma n=11 vs normal brain n=4; xenograft tumor volume ~800 mm^3 ±71.6 in model context; n=3 for some assays, P≤0.001 | Khan, Muzumdar, Shiras; Neoplasia; 2019; Jan | https://doi.org/10.1016/j.neo.2018.11.005 | (khan2019attenuationoftumor pages 4-6, khan2019attenuationoftumor pages 1-2, khan2019attenuationoftumor pages 2-3, khan2019attenuationoftumor media a83ab1b6) |
| hnRNPL | BioGRID-guided candidate identification; co-IP and GST pull-down; TUBE2 ubiquitination enrichment; CHX half-life; MG132 rescue; in vitro ubiquitination with Cul1-Skp1-Rbx1 + FBXO16; rescue/phenocopy functional assays | SCF/CUL1-SKP1-RBX1-dependent ubiquitination and proteasomal degradation of hnRNPL | F-box required for ubiquitination activity; C-terminal region required for substrate recognition; binds hnRNPL RRM3 domain | FBXO16 reported mainly nuclear; hnRNPL mainly nuclear | Human ovarian cancer cells; SKOV3 xenograft | Negative FBXO16-hnRNPL correlation in 68 ovarian cancer specimens (χ²=14.81, P<0.001); hnRNPL ΔRRM3 xenograft using 1×10^7 cells, n=5 mice, significantly increased tumor growth (P<0.001); FBXO16 loss increased proliferation, clonogenicity, invasion | Ji et al.; Cell Death & Disease; 2021; Jul | https://doi.org/10.1038/s41419-021-04040-9 | (ji2021fbxo16mediatedhnrnplubiquitination pages 1-2, ji2021fbxo16mediatedhnrnplubiquitination pages 6-8, ji2021fbxo16mediatedhnrnplubiquitination pages 4-6, ji2021fbxo16mediatedhnrnplubiquitination pages 8-9) |
| ULK1 | Co-IP/in vitro interaction; ubiquitination assays; FBXO16 knockdown/overexpression; autophagy and proliferation assays; truncation-mutant testing | K48-linked polyubiquitination of ULK1 with proteasomal targeting; FBXO16 suppresses ULK1-dependent autophagy | C-terminal region implicated based on ΔCTD testing in binding and functional assays | Not explicitly localized in excerpt; mechanism studied in cellular protein turnover/autophagy context | Human high-grade serous ovarian cancer models | FBXO16 knockdown increased ULK1 protein while not affecting ATG7/ATG13/Beclin-1; FBXO16 overexpression decreased ULK1, lowered LC3II/I ratio, increased p62; no cohort HR/effect size reported in excerpt | Zhang et al.; Cell Death & Disease; 2024; Oct | https://doi.org/10.1038/s41419-024-07120-8 | (zhang2024mir937amplificationpotentiates pages 7-10) |
| NF-κB p65 (RELA) | siRNA screen of 39 Fbxo genes; co-IP with PDLIM2/CUL1/SKP1; polyubiquitination assays; nuclear fractionation; ELAM-1 luciferase; knockdown/deficiency functional assays | Polyubiquitination and proteasomal degradation of p65 within a PDLIM2-containing CRL1/SCF-like complex; loss of Fbxo16 increases nuclear p65 and inflammatory cytokines | F-box domain required for CUL1/PDLIM2 complex formation and p65 polyubiquitination; ΔF mutant impaired | Nuclear/intranuclear, including insoluble nuclear fraction | Dendritic cells; HEK293T, BMDCs, MEFs; inflammatory signaling rather than cancer | Screened 39 Fbxo genes; Fbxo16 deficiency caused striking augmentation of LPS-induced IL-6 and enhanced nuclear p65; WT but not ΔF suppressed NF-κB luciferase activity; no hazard ratios reported | Sugimoto-Ishige, Jodo, Tanaka; Frontiers in Immunology; 2025; Jun | https://doi.org/10.3389/fimmu.2025.1524110 | (sugimotoishige2025fbxo16mediatesdegradation pages 8-9, sugimotoishige2025fbxo16mediatesdegradation pages 6-7, sugimotoishige2025fbxo16mediatesdegradation pages 12-13, sugimotoishige2025fbxo16mediatesdegradation pages 7-8, sugimotoishige2025fbxo16mediatesdegradation pages 5-6) |
| SKP1 / CUL1 / RBX1 (SCF components) | Interaction/co-complex evidence; in vitro ubiquitination with Cul1-Skp1-Rbx1 plus FBXO16; co-IP with CUL1/SKP1; dominant-negative CUL1 effects | Supports FBXO16 as the substrate-recognition module of canonical SCF/CRL1 E3 ligase rather than a substrate itself | F-box domain mediates SCF assembly/function | Nuclear context emphasized in ovarian cancer and p65 studies; broader cytoplasmic+nuclear localization also reported | Human ovarian cancer cells; HEK293T; dendritic cell signaling | Dominant-negative CUL1 caused hnRNPL accumulation; Fbxo16 binds CUL1/SKP1 but not CUL2/CUL3 in immune study; quantitative interaction values not provided | Ji et al.; Cell Death & Disease; 2021; Jul; Sugimoto-Ishige et al.; Frontiers in Immunology; 2025; Jun | https://doi.org/10.1038/s41419-021-04040-9 ; https://doi.org/10.3389/fimmu.2025.1524110 | (ji2021fbxo16mediatedhnrnplubiquitination pages 6-8, ji2021fbxo16mediatedhnrnplubiquitination pages 4-6, sugimotoishige2025fbxo16mediatesdegradation pages 6-7) |
| PDLIM2 | Co-IP/complex assembly evidence in p65-targeting study | Partner in a PDLIM2-containing CRL1 complex that enables p65 recruitment, polyubiquitination, and degradation | F-box domain needed for proper complex formation with CUL1/PDLIM2 | Nuclear/intranuclear | Dendritic cells; HEK293T reconstitution system | Fbxo16 knockdown was the key hit reverting PDLIM2-dependent p65 decrease in screen-derived follow-up; no explicit effect size in excerpt | Sugimoto-Ishige, Jodo, Tanaka; Frontiers in Immunology; 2025; Jun | https://doi.org/10.3389/fimmu.2025.1524110 | (sugimotoishige2025fbxo16mediatesdegradation pages 8-9, sugimotoishige2025fbxo16mediatesdegradation pages 6-7, sugimotoishige2025fbxo16mediatesdegradation pages 5-6) |
Table: This table compiles experimentally supported evidence for human FBXO16 (UniProt Q8IX29), emphasizing validated substrates, SCF/CRL1 complex partners, domain requirements, compartment, biological context, and quantitative findings. It is useful as a compact functional-annotation map grounded in primary literature and citeable context IDs.
Zhang Z et al. MIR937 amplification potentiates ovarian cancer progression by attenuating FBXO16 inhibition on ULK1-mediated autophagy. Cell Death & Disease. Oct 2024. https://doi.org/10.1038/s41419-024-07120-8 (zhang2024mir937amplificationpotentiates pages 7-10)
Open Targets Platform (disease–target association aggregation for FBXO16). Accessed via tool output. https://platform.opentargets.org/ (OpenTargets Search: -FBXO16)
References
(ji2021fbxo16mediatedhnrnplubiquitination pages 1-2): Mei Ji, Zhao Zhao, Yue Li, Penglin Xu, Jia Shi, Zhe Li, Kaige Wang, Xiaotian Huang, Jing Ji, Wei Liu, and Bin Liu. Fbxo16-mediated hnrnpl ubiquitination and degradation plays a tumor suppressor role in ovarian cancer. Cell Death & Disease, Jul 2021. URL: https://doi.org/10.1038/s41419-021-04040-9, doi:10.1038/s41419-021-04040-9. This article has 34 citations and is from a peer-reviewed journal.
(ji2021fbxo16mediatedhnrnplubiquitination pages 6-8): Mei Ji, Zhao Zhao, Yue Li, Penglin Xu, Jia Shi, Zhe Li, Kaige Wang, Xiaotian Huang, Jing Ji, Wei Liu, and Bin Liu. Fbxo16-mediated hnrnpl ubiquitination and degradation plays a tumor suppressor role in ovarian cancer. Cell Death & Disease, Jul 2021. URL: https://doi.org/10.1038/s41419-021-04040-9, doi:10.1038/s41419-021-04040-9. This article has 34 citations and is from a peer-reviewed journal.
(ji2021fbxo16mediatedhnrnplubiquitination pages 4-6): Mei Ji, Zhao Zhao, Yue Li, Penglin Xu, Jia Shi, Zhe Li, Kaige Wang, Xiaotian Huang, Jing Ji, Wei Liu, and Bin Liu. Fbxo16-mediated hnrnpl ubiquitination and degradation plays a tumor suppressor role in ovarian cancer. Cell Death & Disease, Jul 2021. URL: https://doi.org/10.1038/s41419-021-04040-9, doi:10.1038/s41419-021-04040-9. This article has 34 citations and is from a peer-reviewed journal.
(khan2019attenuationoftumor pages 4-6): Mohsina Khan, Dattatraya Muzumdar, and Anjali Shiras. Attenuation of tumor suppressive function of fbxo16 ubiquitin ligase activates wnt signaling in glioblastoma. Jan 2019. URL: https://doi.org/10.1016/j.neo.2018.11.005, doi:10.1016/j.neo.2018.11.005. This article has 35 citations and is from a domain leading peer-reviewed journal.
(sugimotoishige2025fbxo16mediatesdegradation pages 8-9): Akiko Sugimoto-Ishige, Aya Jodo, and Takashi Tanaka. Fbxo16 mediates degradation of nf-κb p65 subunit and inhibits inflammatory response in dendritic cells. Frontiers in Immunology, Jun 2025. URL: https://doi.org/10.3389/fimmu.2025.1524110, doi:10.3389/fimmu.2025.1524110. This article has 3 citations and is from a peer-reviewed journal.
(zhang2024mir937amplificationpotentiates pages 7-10): Zhen Zhang, Xinkui Liu, Chu Chu, Yingjie Zhang, Wei Li, Xiaoyan Yu, Qiaoqiao Han, Haoyu Sun, Yunhong Zhang, Xiaoxiao Zhu, Liang Chen, Ran Wei, Nannan Fan, Miaomiao Zhou, and Xia Li. Mir937 amplification potentiates ovarian cancer progression by attenuating fbxo16 inhibition on ulk1-mediated autophagy. Cell Death & Disease, Oct 2024. URL: https://doi.org/10.1038/s41419-024-07120-8, doi:10.1038/s41419-024-07120-8. This article has 5 citations and is from a peer-reviewed journal.
(ji2021fbxo16mediatedhnrnplubiquitination pages 8-9): Mei Ji, Zhao Zhao, Yue Li, Penglin Xu, Jia Shi, Zhe Li, Kaige Wang, Xiaotian Huang, Jing Ji, Wei Liu, and Bin Liu. Fbxo16-mediated hnrnpl ubiquitination and degradation plays a tumor suppressor role in ovarian cancer. Cell Death & Disease, Jul 2021. URL: https://doi.org/10.1038/s41419-021-04040-9, doi:10.1038/s41419-021-04040-9. This article has 34 citations and is from a peer-reviewed journal.
(khan2019attenuationoftumor pages 1-2): Mohsina Khan, Dattatraya Muzumdar, and Anjali Shiras. Attenuation of tumor suppressive function of fbxo16 ubiquitin ligase activates wnt signaling in glioblastoma. Jan 2019. URL: https://doi.org/10.1016/j.neo.2018.11.005, doi:10.1016/j.neo.2018.11.005. This article has 35 citations and is from a domain leading peer-reviewed journal.
(sugimotoishige2025fbxo16mediatesdegradation pages 6-7): Akiko Sugimoto-Ishige, Aya Jodo, and Takashi Tanaka. Fbxo16 mediates degradation of nf-κb p65 subunit and inhibits inflammatory response in dendritic cells. Frontiers in Immunology, Jun 2025. URL: https://doi.org/10.3389/fimmu.2025.1524110, doi:10.3389/fimmu.2025.1524110. This article has 3 citations and is from a peer-reviewed journal.
(khan2019attenuationoftumor pages 2-3): Mohsina Khan, Dattatraya Muzumdar, and Anjali Shiras. Attenuation of tumor suppressive function of fbxo16 ubiquitin ligase activates wnt signaling in glioblastoma. Jan 2019. URL: https://doi.org/10.1016/j.neo.2018.11.005, doi:10.1016/j.neo.2018.11.005. This article has 35 citations and is from a domain leading peer-reviewed journal.
(khan2019attenuationoftumor media a83ab1b6): Mohsina Khan, Dattatraya Muzumdar, and Anjali Shiras. Attenuation of tumor suppressive function of fbxo16 ubiquitin ligase activates wnt signaling in glioblastoma. Jan 2019. URL: https://doi.org/10.1016/j.neo.2018.11.005, doi:10.1016/j.neo.2018.11.005. This article has 35 citations and is from a domain leading peer-reviewed journal.
(sugimotoishige2025fbxo16mediatesdegradation pages 7-8): Akiko Sugimoto-Ishige, Aya Jodo, and Takashi Tanaka. Fbxo16 mediates degradation of nf-κb p65 subunit and inhibits inflammatory response in dendritic cells. Frontiers in Immunology, Jun 2025. URL: https://doi.org/10.3389/fimmu.2025.1524110, doi:10.3389/fimmu.2025.1524110. This article has 3 citations and is from a peer-reviewed journal.
(OpenTargets Search: -FBXO16): Open Targets Query (-FBXO16, 5 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.
(sugimotoishige2025fbxo16mediatesdegradation pages 12-13): Akiko Sugimoto-Ishige, Aya Jodo, and Takashi Tanaka. Fbxo16 mediates degradation of nf-κb p65 subunit and inhibits inflammatory response in dendritic cells. Frontiers in Immunology, Jun 2025. URL: https://doi.org/10.3389/fimmu.2025.1524110, doi:10.3389/fimmu.2025.1524110. This article has 3 citations and is from a peer-reviewed journal.
(sugimotoishige2025fbxo16mediatesdegradation pages 5-6): Akiko Sugimoto-Ishige, Aya Jodo, and Takashi Tanaka. Fbxo16 mediates degradation of nf-κb p65 subunit and inhibits inflammatory response in dendritic cells. Frontiers in Immunology, Jun 2025. URL: https://doi.org/10.3389/fimmu.2025.1524110, doi:10.3389/fimmu.2025.1524110. This article has 3 citations and is from a peer-reviewed journal.