# BTRC (gene)
**BTRC** (beta-transducin repeat containing E3 ubiquitin protein ligase; Gene ID 8945) is a human protein-coding gene on chromosome 10 at 10q24 that encodes β-TrCP1, the substrate-recognition subunit of the SCF^β-TrCP E3 ubiquitin ligase complex[1](https://www.ncbi.nlm.nih.gov/gene/8945) • [2](https://febs.onlinelibrary.wiley.com/doi/10.1111/febs.15585). The encoded protein binds phosphorylated target proteins and directs them for ubiquitination and proteasomal degradation, controlling regulators of Wnt signaling, NF-κB signaling, the cell cycle, and the DNA damage response[3](https://pmc.ncbi.nlm.nih.gov/articles/PMC3374336/) • [4](https://www.proteinatlas.org/ENSG00000166167-BTRC).
| Key fact | Detail |
|---|---|
| Official name | beta-transducin repeat containing E3 ubiquitin protein ligase; HGNC:1144; protein coding; RefSeq status REVIEWED[1](https://www.ncbi.nlm.nih.gov/gene/8945) |
| Protein | β-TrCP1 (also FBXW1, FBXW1A, FWD1), 69 kDa, 605 amino acids[2](https://febs.onlinelibrary.wiley.com/doi/10.1111/febs.15585) |
| Location | Chromosome 10, region 10q24[2](https://febs.onlinelibrary.wiley.com/doi/10.1111/febs.15585) |
| Structure | N-terminal F-box motif (about 40 amino acids) and seven C-terminal WD-40 repeats for substrate binding[3](https://pmc.ncbi.nlm.nih.gov/articles/PMC3374336/) |
| Substrate motif | Consensus DSGxxS degron (and variants such as DSG/DDG/EEG/SSG/TSGxxS/E/D), whose serine or threonine residues must be phosphorylated before recognition[3](https://pmc.ncbi.nlm.nih.gov/articles/PMC3374336/) • [5](https://pmc.ncbi.nlm.nih.gov/articles/PMC7206145/) |
| Paralog | FBXW11 encodes β-TrCP2 (62 kDa, 542 amino acids) on chromosome 5; the two paralogs cross-regulate each other[2](https://febs.onlinelibrary.wiley.com/doi/10.1111/febs.15585) • [5](https://pmc.ncbi.nlm.nih.gov/articles/PMC7206145/) |
| Clinical annotation | Prognostic marker in glioblastoma multiforme, kidney renal clear cell carcinoma, and ovary serous cystadenocarcinoma[4](https://www.proteinatlas.org/ENSG00000166167-BTRC) |
## Structure and the SCF complex
BTRC belongs to the Fbws class of the [F-box protein family](https://www.edgepedia.org/f-box-protein-family), one of 69 human F-box proteins, characterized by an approximately 40 amino acid F-box motif plus multiple WD-40 repeats[6](https://pmc.ncbi.nlm.nih.gov/articles/PMC10317156/) • [4](https://www.proteinatlas.org/ENSG00000166167-BTRC). As a substrate receptor, β-TrCP assembles the [SCF complex](https://www.edgepedia.org/scf-complex), also known as cullin-RING ligase 1 (CRL1): the F-box binds the adaptor protein SKP1, cullin-1 (CUL1) acts as a molecular scaffold, and the RING protein RBX1 serves as the ligase activity center that recruits the ubiquitination machinery[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC7206145/). The paralogs also contain a D-domain, a dimerization domain, at their N terminus, and can form homodimers or heterodimers with differential potency in promoting substrate degradation[2](https://febs.onlinelibrary.wiley.com/doi/10.1111/febs.15585) • [7](https://pmc.ncbi.nlm.nih.gov/articles/PMC10487276/).
## Substrate recognition
Recognition is not strictly phosphorylation-dependent: while phosphorylated degrons are the most common mechanism of substrate recognition by F-box proteins, substrates can also be recognized through diverse degron mechanisms dependent on or independent of post-translational modifications, and when phosphorylation is required, the serine or threonine residues within the degron motif must be phosphorylated by specific kinases before β-TrCP can bind[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC7206145/) • [17](https://www.nature.com/articles/nrm3582). For example, the degron sequence in β-catenin is phosphorylated by GSK3 and CKI before SCF^β-TrCP can efficiently bind and mediate ubiquitination of the target[3](https://pmc.ncbi.nlm.nih.gov/articles/PMC3374336/). Most β-TrCP substrates contain a consensus DSGΦxS degron, in which Φ represents a hydrophobic amino acid and x can be any amino acid[8](https://hub.hku.hk/bitstream/10722/234400/1/content.pdf). This signal-dependent phosphorylation of substrates is the principal way the ligase's activity is regulated from outside[9](https://cshperspectives.cshlp.org/content/2/2/a000166.full.pdf).
## Substrates and pathways
The well-characterized substrates of β-TrCP include tumor suppressors such as Bim EL, IκB, PDCD4, and CDC25A, and oncoproteins such as β-catenin, YAP, and WEE1, giving the ligase both tumor-promoting and tumor-suppressing characteristics depending on the substrate[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC7206145/). SCF(BTRC) mediates the ubiquitination of CTNNB1 (β-catenin) as part of Wnt signaling, and of phosphorylated NFKB1, ATF4, CDC25A, DLG1, FBXO5, PER1, SMAD3, SMAD4, and SNAI1[4](https://www.proteinatlas.org/ENSG00000166167-BTRC).
**NF-κB activation.** BTRC ubiquitinates phosphorylated [NFKBIA](https://www.edgepedia.org/nfkbia) (IκBα), targeting it for degradation and thereby freeing the associated NFKB1 to translocate into the nucleus and activate transcription; ubiquitination of NFKBIA occurs at Lys-21 and Lys-22[1](https://www.ncbi.nlm.nih.gov/gene/8945) • [4](https://www.proteinatlas.org/ENSG00000166167-BTRC). BTRC is required for activation of NF-κB-mediated transcription by [IL1B](https://www.edgepedia.org/il1b), MAP3K14, MAP3K1, IKBKB, and TNF[4](https://www.proteinatlas.org/ENSG00000166167-BTRC).
**Other roles.** SCF(BTRC) ubiquitination of CEP68 is required for centriole separation during mitosis, degradation of phosphorylated PER1 and [PER2](https://www.edgepedia.org/per2) gives the protein an essential role in clock-dependent transcription, and the protein is required for proteolytic processing of GLI3[4](https://www.proteinatlas.org/ENSG00000166167-BTRC). It also mediates ubiquitination of [REST](https://www.edgepedia.org/rest-gene) and of KLF4, negatively regulating cell pluripotency maintenance and embryogenesis[4](https://www.proteinatlas.org/ENSG00000166167-BTRC).
**Virus exploitation.** The encoded protein mediates degradation of CD4 through its interaction with HIV-1 Vpu[4](https://www.proteinatlas.org/ENSG00000166167-BTRC). The Vpu SGNES degron has dual functionality: it acts as a dominant-negative decoy that binds β-TrCP and prevents its participation in the NF-κB pathway, and it recruits the SCF^β-TrCP ligase to ubiquitinate and degrade the viral targets CD4 and tetherin[10](https://pmc.ncbi.nlm.nih.gov/articles/PMC10470808/).
## The two paralogs and their cross talk
β-TrCP is highly conserved from [Drosophila](https://www.edgepedia.org/drosophila) to human and is encoded by a single gene in invertebrates, whereas mammalian genomes contain two distinct paralogs, β-TrCP1 (BTRC, also FBXW1) and β-TrCP2 (FBXW11, also FBXW1B and HOS)[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC7206145/). Although the two paralogs act redundantly and show selectivity for certain unique substrates, mouse knock-out experiments reveal distinct preferred targets: β-TrCP2 is required for early development, whereas losing β-TrCP1 leaves animals viable but disrupts sperm formation and lowers fertility.[7](https://pmc.ncbi.nlm.nih.gov/articles/PMC10487276/) • [11](https://www.sciencedirect.com/science/article/pii/S0898656810003414) • [18](https://www.nature.com/articles/s41418-019-0402-x)
The paralogs also regulate each other directly. Each is a physiological substrate of the other's SCF ligase, and this mutual targeting depends on their own β-TrCP degron sequences[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC7206145/). Under glucose deprivation or serum starvation, AMPK is activated and phosphorylates β-TrCP1, which is then ubiquitinated and degraded by SCF^β-TrCP2; β-TrCP2 is not correspondingly degraded by β-TrCP1 under these conditions[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC7206145/) • [7](https://pmc.ncbi.nlm.nih.gov/articles/PMC10487276/). Functionally, β-TrCP2, not β-TrCP1, preferentially degrades DEPTOR and REDD1, the inhibitors of mTORC1, thereby activating mTORC1, inhibiting autophagy, and promoting cell growth, while β-TrCP1 suppresses cell growth[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC7206145/) • [7](https://pmc.ncbi.nlm.nih.gov/articles/PMC10487276/).
## Cancer relevance
Because SCF^β-TrCP ligases regulate cell division and signal transduction pathways essential for tumorigenesis, β-TrCP has been studied as a target for anticancer therapy, and its regulation is aberrant in human and animal cancer[12](https://www.nature.com/articles/1207389). In triple-negative breast cancer cells, β-TrCP2 inhibits autophagy and senescence and promotes cell proliferation and migration, whereas β-TrCP1 suppresses cell growth[7](https://pmc.ncbi.nlm.nih.gov/articles/PMC10487276/). β-TrCP2, but not β-TrCP1, can mediate ubiquitination and degradation of ZNF281, inhibiting colorectal cancer progression, and the β-TrCP1-FBXW2-SKP2 axis forms an oncogene-tumor suppressor-oncogene cascade controlling cancer cell growth[13](https://pmc.ncbi.nlm.nih.gov/articles/PMC7086354/).
At the clinical annotation level, the Human Protein Atlas lists BTRC as a prognostic marker in glioblastoma multiforme, kidney renal clear cell carcinoma, and ovary serous cystadenocarcinoma[4](https://www.proteinatlas.org/ENSG00000166167-BTRC).
## Expression and localization
The gene produces 4 protein-coding transcripts, and the encoded protein interacts with 25 proteins[4](https://www.proteinatlas.org/ENSG00000166167-BTRC). Endogenous β-TrCP1 and β-TrCP2 both localize to the nucleus and the cytosol[11](https://www.sciencedirect.com/science/article/pii/S0898656810003414); the Human Protein Atlas places the main subcellular location in the nucleoplasm, with additional localization to the plasma membrane and cytosol[4](https://www.proteinatlas.org/ENSG00000166167-BTRC). RNA expression shows low tissue specificity across normal tissues, and the protein is not detected in blood by immunoassay or mass spectrometry[4](https://www.proteinatlas.org/ENSG00000166167-BTRC).
The gene is conserved across vertebrates with annotated orthologs: the mouse Btrc gene on chromosome 19 has 21 exons, and the chicken BTRC gene on chromosome 6 has 20 exons[14](https://www.ncbi.nlm.nih.gov/gene/12234) • [15](https://www.ncbi.nlm.nih.gov/gene/423854). β-TrCP was originally identified as a suppressor of a temperature-sensitive mutation in the budding yeast CDC15 gene, though its mechanism of suppression was not determined[16](https://genesdev.cshlp.org/content/13/3/270.full.pdf).
## References
1. [BTRC beta-transducin repeat containing E3 ubiquitin protein ligase [Homo sapiens], NCBI Gene ID 8945](https://www.ncbi.nlm.nih.gov/gene/8945)
2. [Bi et al. (2021). The characteristics and roles of β-TrCP1/2 in carcinogenesis. The FEBS Journal](https://febs.onlinelibrary.wiley.com/doi/10.1111/febs.15585)
3. [The Fbw7 and Beta-TRCP E3 ubiquitin ligases and their roles in tumorigenesis, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC3374336/)
4. [BTRC protein expression summary, The Human Protein Atlas](https://www.proteinatlas.org/ENSG00000166167-BTRC)
5. [The cross talk of two family members of β-TrCP in the regulation of cell autophagy and growth, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC7206145/)
6. [Small molecule and peptide inhibitors of βTrCP and the βTrCP–NRF2 protein–protein interaction, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC10317156/)
7. [Beta-Transducin Repeats-Containing Proteins as an Anticancer Target, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC10487276/)
8. [β-TrCP-mediated ubiquitination and degradation of liver-enriched transcription factor CREB-H, HKU](https://hub.hku.hk/bitstream/10722/234400/1/content.pdf)
9. [F-box proteins: the concept, Cold Spring Harbor Perspectives in Biology](https://cshperspectives.cshlp.org/content/2/2/a000166.full.pdf)
10. [Differential dysregulation of β-TrCP1 and -2 by HIV-1 Vpu, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC10470808/)
11. [Specificity, location and function of βTrCP isoforms and their splice variants, Cellular Signalling](https://www.sciencedirect.com/science/article/pii/S0898656810003414)
12. [Fuchs, Spiegelman & Suresh Kumar (2004). The many faces of β-TrCP E3 ubiquitin ligases. Oncogene 23, 2028–2036](https://www.nature.com/articles/1207389)
13. [F-box proteins and cancer: an update, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC7086354/)
14. [Btrc beta-transducin repeat containing protein [Mus musculus], NCBI Gene ID 12234](https://www.ncbi.nlm.nih.gov/gene/12234)
15. [BTRC beta-transducin repeat containing E3 ubiquitin protein ligase [Gallus gallus], NCBI Gene ID 423854](https://www.ncbi.nlm.nih.gov/gene/423854)
16. [Recognition of phosphorylated destruction motifs in IκBα and β-catenin by β-TRCP, Genes & Development](https://genesdev.cshlp.org/content/13/3/270.full.pdf)
17. [Mechanisms and function of substrate recruitment by F-box proteins, Nature Reviews Molecular Cell Biology](https://www.nature.com/articles/nrm3582)
18. [The cross talk of two family members of β-TrCP in the regulation of cell autophagy and growth, Cell Death & Differentiation](https://www.nature.com/articles/s41418-019-0402-x)
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*Topic: Encyclopedia › Life and health › Biological foundations › Biochemistry and metabolism › Protein families and complexes › Structural, chaperone, and RNA-binding protein families › Conserved repeat and scaffold-domain families › F-box protein family*
*Initially written Sep 17, 2026 · Reviewed: Oct 21, 2026 · Edited: Oct 15, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*
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License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license