ZSWIM8 encodes the substrate-recognition component of a Cullin-RING E3 ubiquitin ligase complex that recognizes Argonaute-miRNA complexes engaged with highly complementary target RNAs and promotes target-directed miRNA degradation. Human and metazoan evidence supports a CUL3/RBX1/ELOB/ELOC/ZSWIM8 complex, ubiquitin-proteasome-dependent AGO turnover, and an additional protein quality-control role toward intrinsically disordered substrates such as DAB1.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
|
GO:0031462
Cul2-RING ubiquitin ligase complex
|
IBA
GO_REF:0000033 |
MODIFY |
Summary: Directionally correct as a Cullin-RING ligase annotation, but current human experimental evidence supports ZSWIM8 as part of a CUL3-containing CRL rather than a CUL2-RING ligase complex.
Reason: The ZSWIM8-ELOB-ELOC adaptor module was tested against CUL2, CUL5, and CUL3 in the TDMD screen follow-up; CUL3, not CUL2, was required. The existing IDA annotation to Cul3-RING ubiquitin ligase complex is the appropriate replacement for the human protein.
Proposed replacements:
Cul3-RING ubiquitin ligase complex
Supporting Evidence:
PMID:33184234
In contrast, CUL3 knockout strongly repressed the reporter, suggesting that the ZSWIM8 E3 ligase represents a CRL in which ZSWIM8-ELOB-ELOC serve as substrate adapters for CUL3.
|
|
GO:0005829
cytosol
|
IEA
GO_REF:0000044 |
ACCEPT |
Summary: Cytosolic localization is consistent with UniProt and with ZSWIM8 acting on AGO-miRNA complexes and cytosolic protein quality-control substrates.
Reason: Although localization is not itself the catalytic function, cytosol is a supported site for ZSWIM8 activity and is appropriate to retain.
Supporting Evidence:
file:human/ZSWIM8/ZSWIM8-uniprot.txt
SUBCELLULAR LOCATION: Cytoplasm, cytosol
|
|
GO:0008270
zinc ion binding
|
IEA
GO_REF:0000002 |
KEEP AS NON CORE |
Summary: ZSWIM8 contains a SWIM zinc-finger domain, so the IEA zinc-ion-binding annotation is plausible as a domain-level molecular feature.
Reason: The zinc-finger feature supports retention, but the biologically informative core function is substrate-adaptor activity in a CRL rather than generic zinc binding.
Supporting Evidence:
file:human/ZSWIM8/ZSWIM8-uniprot.txt
Znf_SWIM. (IPR007527)
|
|
GO:0016567
protein ubiquitination
|
IEA
GO_REF:0000041 |
ACCEPT |
Summary: Protein ubiquitination is supported by UniProt pathway annotation and by experimental studies showing ZSWIM8 functions as the substrate adaptor of a Cullin-RING E3 ubiquitin ligase.
Reason: ZSWIM8 is not the catalytic RING subunit, but as the substrate-recognition component of the CRL it directly enables ubiquitination of recruited substrates.
Supporting Evidence:
PMID:33184234
We identified a cullin-RING ubiquitin ligase (CRL), containing the substrate adaptor ZSWIM8, that mediates TDMD.
|
|
GO:0006515
protein quality control for misfolded or incompletely synthesized proteins
|
IDA
PMID:35989311 The ZSWIM8 ubiquitin ligase regulates neurodevelopment by gu... |
ACCEPT |
Summary: ZSWIM8-dependent protein quality control is supported by knockout and mechanistic work showing ZSWIM8 controls DAB1 quality in neurodevelopment.
Reason: The annotation captures a direct substrate-quality-control role for the ZSWIM8 ligase, distinct from but mechanistically related to its TDMD role.
Supporting Evidence:
PMID:35989311
Mechanistic studies reveal that ZSWIM8 controls protein quality of Disabled 1 (Dab1), a key signal molecule for brain development, thus protecting the signaling strength of Dab1.
|
|
GO:0140958
target-directed miRNA degradation
|
IMP
PMID:33184237 The ZSWIM8 ubiquitin ligase mediates target-directed microRN... |
ACCEPT |
Summary: This is a core ZSWIM8 biological process: loss-of-function studies show that the ZSWIM8 CRL is required for target-directed miRNA degradation.
Reason: The annotation is specific, experimentally supported, and captures the best-characterized conserved process mediated by ZSWIM8.
Supporting Evidence:
PMID:33184237
We found that this target-directed miRNA degradation (TDMD) required the ZSWIM8 Cullin-RING E3 ubiquitin ligase.
file:human/ZSWIM8/ZSWIM8-deep-research-falcon.md
ZSWIM8 is best-supported as the substrate-recognition subunit of a Cullin-RING ubiquitin ligase (CRL) complex that executes TDMD by targeting Argonaute proteins.
|
|
GO:0005829
cytosol
|
ISS
GO_REF:0000024 |
ACCEPT |
Summary: The sequence-similarity transfer to cytosol is consistent with UniProt and with the cytosolic AGO-miRNA and protein quality-control contexts of ZSWIM8.
Reason: This duplicates the IEA localization evidence but is not contradicted by experimental or curated summaries.
Supporting Evidence:
file:human/ZSWIM8/ZSWIM8-uniprot.txt
SUBCELLULAR LOCATION: Cytoplasm, cytosol
|
|
GO:0016567
protein ubiquitination
|
IDA
PMID:33184234 A ubiquitin ligase mediates target-directed microRNA decay i... |
ACCEPT |
Summary: Directly supported by the TDMD study identifying ZSWIM8 as the substrate adaptor in a Cullin-RING ubiquitin ligase that acts on AGO-miRNA complexes.
Reason: ZSWIM8 recruits substrates to the ubiquitination machinery, making this process annotation appropriate even though the catalytic RING activity is supplied by the CRL complex.
Supporting Evidence:
PMID:33184234
The ZSWIM8 CRL interacts with AGO proteins, promotes TDMD in a tailing and trimming-independent manner, and regulates miRNA expression in multiple cell types.
|
|
GO:0031463
Cul3-RING ubiquitin ligase complex
|
IDA
PMID:33184234 A ubiquitin ligase mediates target-directed microRNA decay i... |
ACCEPT |
Summary: The Cul3-RING ubiquitin ligase complex annotation is the experimentally supported complex context for human ZSWIM8.
Reason: CUL3 was required in the CRISPR screen validation, while CUL2 and CUL5 knockouts were not, supporting CUL3 as the relevant cullin scaffold.
Supporting Evidence:
PMID:33184234
In contrast, CUL3 knockout strongly repressed the reporter, suggesting that the ZSWIM8 E3 ligase represents a CRL in which ZSWIM8-ELOB-ELOC serve as substrate adapters for CUL3.
|
|
GO:0043161
proteasome-mediated ubiquitin-dependent protein catabolic process
|
IDA
PMID:33184234 A ubiquitin ligase mediates target-directed microRNA decay i... |
ACCEPT |
Summary: ZSWIM8-mediated TDMD proceeds through ubiquitin-proteasome-dependent turnover of AGO-containing complexes, so this process annotation is supported.
Reason: The annotation is broader than target-directed miRNA degradation but accurately captures the proteasome-dependent degradation step mediated by the ZSWIM8 CRL.
Supporting Evidence:
PMID:33184234
These findings suggest a model in which the ZSWIM8 ubiquitin ligase mediates TDMD by directing proteasomal decay of miRNA-containing complexes engaged with highly complementary targets.
|
|
GO:1990756
ubiquitin-like ligase-substrate adaptor activity
|
IDA
PMID:33184234 A ubiquitin ligase mediates target-directed microRNA decay i... |
ACCEPT |
Summary: This molecular-function term captures ZSWIM8's core role as the substrate-recognition component of the TDMD Cullin-RING ubiquitin ligase.
Reason: ZSWIM8 binds AGO proteins engaged with TDMD targets and recruits them to the CUL3 CRL, which is exactly substrate-adaptor activity.
Supporting Evidence:
PMID:33184234
We identified a cullin-RING ubiquitin ligase (CRL), containing the substrate adaptor ZSWIM8, that mediates TDMD.
|
|
GO:1990756
ubiquitin-like ligase-substrate adaptor activity
|
IDA
PMID:33184237 The ZSWIM8 ubiquitin ligase mediates target-directed microRN... |
ACCEPT |
Summary: Independent TDMD work also supports ZSWIM8 as the Cullin-RING ligase adaptor required for target-directed miRNA degradation.
Reason: The annotation is a core molecular function and is supported by loss-of-function evidence linking the ZSWIM8 CRL to AGO proteolysis and miRNA degradation.
Supporting Evidence:
PMID:33184237
This and other findings support a mechanistic model of TDMD in which target-directed proteolysis of AGO by the ubiquitin-proteasome pathway exposes the miRNA for degradation.
PMID:33184234
We identified a cullin-RING ubiquitin ligase (CRL), containing the substrate adaptor ZSWIM8, that mediates TDMD.
|
|
GO:2000627
positive regulation of miRNA catabolic process
|
IDA
PMID:33184234 A ubiquitin ligase mediates target-directed microRNA decay i... |
MODIFY |
Summary: ZSWIM8 positively regulates miRNA catabolism by mediating TDMD of miRNAs engaged with highly complementary target RNAs.
Reason: The term is directionally correct but less specific than the current GO term for the experimentally demonstrated process, target-directed miRNA degradation.
Proposed replacements:
target-directed miRNA degradation
Supporting Evidence:
PMID:33184234
The requirement for the ZSWIM8 ubquitin ligase in TDMD induced by two unrelated substrates in different cell lines suggests that it functions broadly in this pathway.
|
|
GO:2000627
positive regulation of miRNA catabolic process
|
IDA
PMID:33184237 The ZSWIM8 ubiquitin ligase mediates target-directed microRN... |
MODIFY |
Summary: The Bartel study supports the same positive regulatory role for ZSWIM8 in miRNA catabolism through the TDMD pathway.
Reason: The annotation should be replaced by the more specific TDMD process term, which captures the tested biology without relying on a broad parent-like regulation term.
Proposed replacements:
target-directed miRNA degradation
Supporting Evidence:
PMID:33184237
loss-of-function studies indicated that the ZSWIM8 Cullin-RING ligase accelerates degradation of numerous miRNAs in cells of mammals, flies, and nematodes
|
Q: Which endogenous human TDMD targets account for the strongest ZSWIM8-dependent miRNA half-life changes across cell types?
Q: Does ZSWIM8 use the same substrate-recognition surface for AGO-miRNA complexes and intrinsically disordered protein quality-control substrates such as DAB1?
Q: Is the Cul2-RING IBA annotation a legacy transfer from non-human EBAX systems that should be corrected upstream to Cul3-RING ubiquitin ligase complex?
Experiment: Endogenous-tag ZSWIM8, CUL3, ELOB, and ELOC in human cells and perform target-triggered AGO proximity labeling with and without TDMD-inducing transcripts.
Hypothesis: ZSWIM8 recruits AGO-miRNA complexes to a CUL3 CRL specifically when TDMD target pairing exposes the AGO-bound miRNA.
Type: proteomics/proximity labeling
Experiment: Mutational separation of ZSWIM8 SWIM/TPR/C-terminal regions followed by rescue assays for miR-7 TDMD and DAB1 protein quality control.
Hypothesis: Distinct substrate-recognition modules contribute to AGO-dependent TDMD and DAB1 quality-control functions.
Type: structure-function rescue
Experiment: Comparative CRL assembly assays testing CUL2, CUL3, and CUL5 binding to human ZSWIM8-ELOB-ELOC under endogenous expression conditions.
Hypothesis: Human ZSWIM8 preferentially forms a functional CUL3-RING ubiquitin ligase complex rather than a Cul2-RING complex.
Type: biochemical reconstitution/co-immunoprecipitation
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 synthesized here refers to human ZSWIM8 (synonym KIAA0913) and explicitly matches the UniProt-provided identity (A7E2V4), describing it as a large (~1837 aa) protein containing a BC box, Cullin box, and SWIM zinc-finger domain, functioning as the substrate-recognition component of a Cullin–RING E3 ubiquitin ligase involved in miRNA turnover. (buhagiar2024tokilla pages 3-4)
TDMD is a regulated miRNA turnover pathway in which an AGO-bound miRNA engages a “trigger RNA” with unusually extensive complementarity (especially beyond the seed), leading to miRNA decay rather than target repression. Reviews emphasize that TDMD triggers recruit the ZSWIM8 E3 ubiquitin ligase complex to the AGO–miRNA complex, leading to AGO ubiquitination, proteasomal degradation of AGO, and subsequent destruction of the now-unprotected miRNA by cellular nucleases. (hiers2024target‐directedmicrornadegradation pages 1-3, buhagiar2024tokilla pages 3-4)
ZSWIM8 is best-supported as the substrate-recognition subunit of a Cullin–RING ubiquitin ligase (CRL) complex that executes TDMD by targeting Argonaute proteins. Domain/motif mapping in a 2024 authoritative review describes a BC box (aa 73–88) (Elongin-binding), a Cullin box (aa 100–108), and a SWIM domain (aa 174–208). (buhagiar2024tokilla pages 3-4)
Genome-scale screening for TDMD factors identified a CRL machinery involving ZSWIM8 together with core ubiquitin-ligase components including ELOB, ELOC, CUL3, RBX1, ARIH1, and NEDD8-pathway genes (consistent with a neddylation-activated CRL). (han2020aubiquitinligase pages 2-3)
A 2024 expert review notes that although ZSWIM8 contains a Cullin-box motif predicted to bind CUL2, experiments in human K562 cells show ZSWIM8 co-immunoprecipitates with and requires CUL3 for TDMD, consistent with a functional CUL3–RBX1-type ligase architecture in that context. (buhagiar2024tokilla pages 3-4)
Primary research and reviews converge on a model in which binding of a miRNA to a highly complementary trigger RNA induces a TDMD-competent AGO conformation that is recognized by the ZSWIM8 CRL, resulting in AGO polyubiquitination and proteasomal degradation, which then exposes the bound miRNA to nucleases for degradation. (han2020aubiquitinligase pages 2-3, hiers2024target‐directedmicrornadegradation pages 1-3, buhagiar2024tokilla pages 3-4)
A key mechanistic point from primary work is that TDMD can proceed independently of miRNA tailing and trimming (historically proposed obligate steps): disruption of ZSWIM8 complex components stabilizes TDMD-targeted miRNAs even when tailing/trimming still occur, and TDMD requires ubiquitin transfer/proteasome activity. (han2020aubiquitinligase pages 2-3)
Evidence supports Argonaute proteins as central substrates in ZSWIM8-dependent TDMD. The CRL associates with AGO2 (immunoprecipitation/TurboID in the primary study), and TDMD requires surface-exposed lysines on AGO2; mutation of AGO2 lysines impairs TDMD, implicating AGO ubiquitination or lysine-dependent recognition as a critical step. (han2020aubiquitinligase pages 2-3)
A 2024 review summarizes that ZSWIM8-driven TDMD involves ubiquitination and degradation of all four human AGO proteins, and that TDMD substrates include dozens of miRNAs across animals. (buhagiar2024tokilla pages 3-4)
ZSWIM8-mediated TDMD is described as occurring in the cytoplasmic RISC context (AGO–miRNA complexes engaged with trigger RNAs), consistent with proteasome-dependent turnover of AGO. (zhang2025regulatorymechanismsof pages 2-5, buhagiar2024tokilla pages 3-4)
A 2024 review reports ZSWIM8 as primarily diffuse cytoplasmic, with stress-granule colocalization observed under proteasome/HSP90 inhibition. (buhagiar2024tokilla pages 3-4)
Two 2024 reviews (Nucleic Acids Research; WIREs RNA) synthesize the expanding TDMD field and consolidate ZSWIM8 as the central E3 substrate receptor that links trigger RNA binding to AGO destruction and miRNA turnover; they emphasize growing catalogs of regulated miRNAs and predicted triggers, and highlight methodological best practices for validating trigger RNAs. (buhagiar2024tokilla pages 3-4, hiers2024target‐directedmicrornadegradation pages 1-3)
Quantitatively, the 2024 NAR review reports that >100 miRNAs (107) are regulated by ZSWIM8 across bilaterian animals, and that 12 miRNAs were reported as regulated in human cell lines in the reviewed literature. (buhagiar2024tokilla pages 3-4)
A 2024 bioRxiv study proposes that ZSWIM8 can also act as an E3 controlling abundance of intrinsically disordered region (IDR)-rich RNA-binding proteins during brain development (“disorder-targets-misorder”), reporting that ZSWIM8 deletion caused accumulation of multiple RBPs (including AGO2 and ELAV1) in neonatal brains and impaired oligodendrocyte maturation via the AGO2/miR-7 axis. (lei2024turnoverofrnabinding pages 1-5)
Mechanistically, this work reports miRNA-binding-dependent stimulation of AGO2 ubiquitination: AGO2 ubiquitination by ZSWIM8 is weak at baseline but becomes strong when AGO2 is miRNA-bound (MiR7a in experiments), and an AGO2 mutant defective in miRNA binding (Y529E) is not ubiquitinated. (lei2024turnoverofrnabinding pages 9-14)
A 2024 Nucleic Acids Research study demonstrates a translationally relevant strategy: retargeting validated TDMD sites (especially Cyrano-like architectures) to inhibit heterologous miRNAs, including highly expressed viral miRNAs from Kaposi’s sarcoma-associated herpesvirus (KSHV). Lentiviral delivery of a Cyrano-like inhibitor targeting miR-K11 into KSHV-transformed primary effusion lymphoma (PEL) cells impaired viability, supporting a functional role of miR-K11 in PEL cell survival and highlighting a potential therapeutic direction. (ortega2024retargetingtargetdirectedmicrornadecay pages 1-2)
Importantly, the same study reports that inactivation of ZSWIM8 did not substantially affect miRNA inhibition by these engineered Cyrano-based inhibitors in 293T or PEL cells—indicating that engineered “TDMD-like” inhibitory architectures can function in ways that are not strictly dependent on ZSWIM8 in the tested contexts. (ortega2024retargetingtargetdirectedmicrornadecay pages 1-2, ortega2024retargetingtargetdirectedmicrornadecay pages 2-4)
The engineered inhibitor study reports nonlinearity/saturation: increasing miRNA-inhibiting site number beyond a point did not proportionally improve efficacy, and luciferase sensor rescue plateaued at approximately ~75–80%. (ortega2024retargetingtargetdirectedmicrornadecay pages 10-11)
Authoritative 2024 reviews present a consensus that ZSWIM8 is the core substrate receptor of the CRL that mediates TDMD by recognizing AGO conformational states induced by highly complementary trigger RNAs and promoting proteasome-dependent AGO turnover, thereby specifying miRNA half-lives for a substantial set of miRNAs. (buhagiar2024tokilla pages 3-4, hiers2024target‐directedmicrornadegradation pages 1-3)
While ZSWIM8 is clearly required for canonical TDMD in foundational genetics/biochemistry studies (e.g., CRISPR screens and CRL component dependencies), the 2024 engineered inhibitor work shows that some miRNA inhibition strategies inspired by TDMD triggers can remain effective even when ZSWIM8 is inactivated—suggesting that the field should distinguish (i) ZSWIM8-dependent TDMD (AGO destruction/miRNA decay) from (ii) trigger-inspired inhibitory binding architectures that may act through alternative mechanisms (e.g., stable sequestration) depending on RNA design and cellular context. (han2020aubiquitinligase pages 2-3, ortega2024retargetingtargetdirectedmicrornadecay pages 1-2)
A schematic model figure from the foundational Science study depicts the pathway logic: highly complementary target engagement recruits/activates the ZSWIM8 CRL, which ubiquitinates AGO, leading to proteasomal degradation and release/decay of the miRNA. (han2020aubiquitinligase media 3f782238)
| Topic | Key points | Evidence/citation ids | Primary source | URL/DOI and publication date |
|---|---|---|---|---|
| Identity/domains | Human ZSWIM8 corresponds to UniProt A7E2V4/KIAA0913; ~1837 aa substrate-recognition subunit of a Cullin-RING E3 ligase. Reported motifs include a BC box (aa 73-88), Cullin box (aa 100-108), and SWIM domain (aa 174-208), consistent with the UniProt SWIM-domain family assignment. | (buhagiar2024tokilla pages 3-4) | Buhagiar, Nucleic Acids Research, 2024 | https://doi.org/10.1093/nar/gkae003 ; Jan 2024 |
| E3 ligase complex | ZSWIM8 acts as a CRL substrate adaptor with Elongins B/C and functionally requires CUL3, RBX1, ARIH1, and NEDD8-pathway genes in TDMD screens. Review evidence notes BC-box binding to Elongins B/C and CUL3 association in human cells. | (han2020aubiquitinligase pages 2-3, buhagiar2024tokilla pages 3-4, han2020aubiquitinligase pages 1-2) | Han, Science, 2020 | https://doi.org/10.1126/science.abc9546 ; Dec 2020 |
| Mechanism in TDMD | Trigger RNAs with extensive complementarity to AGO-bound miRNAs induce an AGO conformational state recognized by ZSWIM8. The ligase promotes AGO polyubiquitination and proteasomal degradation, exposing the miRNA to nucleases; tailing/trimming are not required for the core decay mechanism. | (han2020aubiquitinligase pages 2-3, hiers2024target‐directedmicrornadegradation pages 1-3, buhagiar2024tokilla pages 3-4, han2020aubiquitinligase pages 1-2) | Han, Science, 2020; Hiers, WIREs RNA, 2024 | https://doi.org/10.1126/science.abc9546 ; Dec 2020; https://doi.org/10.1002/wrna.1832 ; Mar 2024 |
| Substrates | Direct mechanistic substrate in TDMD is AGO, with all four human AGO proteins discussed in review-level synthesis; AGO2 lysines are important for TDMD. Additional 2024 preprint evidence suggests IDR-rich RNA-binding proteins such as ELAV1/HuR can also be targeted by ZSWIM8 in brain development contexts. | (han2020aubiquitinligase pages 2-3, buhagiar2024tokilla pages 3-4, lei2024turnoverofrnabinding pages 9-14) | Han, Science, 2020; Lei, bioRxiv, 2024 | https://doi.org/10.1126/science.abc9546 ; Dec 2020; https://doi.org/10.1101/2024.01.27.577548 ; Jan 2024 |
| Localization | Available evidence supports primarily diffuse cytoplasmic localization, with stress-granule colocalization under proteasome/HSP90 inhibition; TDMD is described in the cytoplasmic RISC context. | (buhagiar2024tokilla pages 3-4, zhang2025regulatorymechanismsof pages 2-5) | Buhagiar, Nucleic Acids Research, 2024 | https://doi.org/10.1093/nar/gkae003 ; Jan 2024 |
| Quantitative/statistics | In CYRANO-positive K562 cells, depletion of ZSWIM8-complex components increased miR-7 levels by up to ~40-fold. Review synthesis notes regulation of 107 miRNAs across bilaterians and 12 in human cell lines; the 2024 brain preprint reported upregulation of 10 miRNAs and accumulation of 65/180 miRNA-binding proteins upon ZSWIM8 loss. | (han2020aubiquitinligase pages 1-2, buhagiar2024tokilla pages 3-4, lei2024turnoverofrnabinding pages 9-14) | Han, Science, 2020; Buhagiar, Nucleic Acids Research, 2024; Lei, bioRxiv, 2024 | https://doi.org/10.1126/science.abc9546 ; Dec 2020; https://doi.org/10.1093/nar/gkae003 ; Jan 2024; https://doi.org/10.1101/2024.01.27.577548 ; Jan 2024 |
| 2023-2024 developments | 2024 reviews consolidate ZSWIM8 as the central TDMD E3 ligase and emphasize developmental importance and >100 regulated miRNAs across bilateria. A 2024 preprint proposes an expanded model in which ZSWIM8 also recognizes intrinsically disordered proteins in brain development, suggesting substrate-type-specific modes of recognition. | (hiers2024target‐directedmicrornadegradation pages 1-3, buhagiar2024tokilla pages 3-4, lei2024turnoverofrnabinding pages 9-14) | Hiers, WIREs RNA, 2024; Buhagiar, Nucleic Acids Research, 2024; Lei, bioRxiv, 2024 | https://doi.org/10.1002/wrna.1832 ; Mar 2024; https://doi.org/10.1093/nar/gkae003 ; Jan 2024; https://doi.org/10.1101/2024.01.27.577548 ; Jan 2024 |
| Applications/implications | Expert reviews highlight therapeutic potential of manipulating TDMD/miRNA turnover. A 2024 study retargeted TDMD-like sites to inhibit viral or cellular miRNAs, illustrating translational use of the pathway, although that study reported ZSWIM8 was not substantially required for their engineered Cyrano-based inhibitors in tested cells. | (hiers2024target‐directedmicrornadegradation pages 1-3, buhagiar2024tokilla pages 3-4) | Hiers, WIREs RNA, 2024; Buhagiar, Nucleic Acids Research, 2024 | https://doi.org/10.1002/wrna.1832 ; Mar 2024; https://doi.org/10.1093/nar/gkae003 ; Jan 2024 |
Table: This table summarizes the key verified facts about human ZSWIM8 (UniProt A7E2V4), including identity, mechanism, complex composition, localization, quantitative findings, recent developments, and implications. It is useful as a compact evidence map for functional annotation grounded in the cited sources.
Although Open Targets lists genetic associations between ZSWIM8 and several traits/diseases (e.g., atrial fibrillation, aortic stenosis), the full primary-text evidence for these associations was not retrieved in the current corpus; therefore, this report restricts disease-relevance statements to those supported directly by the included sources (e.g., developmental/brain relevance in model systems, and PEL miR-K11 inhibition application) rather than asserting definitive human clinical causality for ZSWIM8. (lei2024turnoverofrnabinding pages 1-5, ortega2024retargetingtargetdirectedmicrornadecay pages 1-2)
References
(buhagiar2024tokilla pages 3-4): Amber F. Buhagiar and Benjamin Kleaveland. To kill a microrna: emerging concepts in target-directed microrna degradation. Nucleic Acids Research, 52:1558-1574, Jan 2024. URL: https://doi.org/10.1093/nar/gkae003, doi:10.1093/nar/gkae003. This article has 56 citations and is from a highest quality peer-reviewed journal.
(hiers2024target‐directedmicrornadegradation pages 1-3): Nicholas M. Hiers, Tianqi Li, Conner M. Traugot, and Mingyi Xie. Target‐directed microrna degradation: mechanisms, significance, and functional implications. Wiley Interdisciplinary Reviews: RNA, Mar 2024. URL: https://doi.org/10.1002/wrna.1832, doi:10.1002/wrna.1832. This article has 36 citations.
(han2020aubiquitinligase pages 2-3): Jaeil Han, Collette A. LaVigne, Benjamin T. Jones, He Zhang, Frank Gillett, and Joshua T. Mendell. A ubiquitin ligase mediates target-directed microrna decay independently of tailing and trimming. Science, Dec 2020. URL: https://doi.org/10.1126/science.abc9546, doi:10.1126/science.abc9546. This article has 246 citations and is from a highest quality peer-reviewed journal.
(zhang2025regulatorymechanismsof pages 2-5): Wenyao Zhang, Lixue Wang, Mohamed Yassine Demna, Jialong Xiong, Maoguo Luo, Yanfeng Wang, and Feng Wang. Regulatory mechanisms of mirna turnover: insights into zswim8-mediated target-directed microrna degradation. Biomedicines, 13:2194, Sep 2025. URL: https://doi.org/10.3390/biomedicines13092194, doi:10.3390/biomedicines13092194. This article has 1 citations.
(lei2024turnoverofrnabinding pages 1-5): Jing Lei, Siming Zhong, Rong Fan, Xin Shu, Guan Wang, Jiansheng Guo, Shuting Xue, Luqian Zheng, Aiming Ren, Junfang Ji, Bing Yang, Shumin Duan, Zhiping Wang, and Xing Guo. Turnover of rna-binding proteins and micrornas by intrinsically disordered region-directed zswim8 ubiquitin ligase during brain development. bioRxiv, Jan 2024. URL: https://doi.org/10.1101/2024.01.27.577548, doi:10.1101/2024.01.27.577548. This article has 1 citations.
(lei2024turnoverofrnabinding pages 9-14): Jing Lei, Siming Zhong, Rong Fan, Xin Shu, Guan Wang, Jiansheng Guo, Shuting Xue, Luqian Zheng, Aiming Ren, Junfang Ji, Bing Yang, Shumin Duan, Zhiping Wang, and Xing Guo. Turnover of rna-binding proteins and micrornas by intrinsically disordered region-directed zswim8 ubiquitin ligase during brain development. bioRxiv, Jan 2024. URL: https://doi.org/10.1101/2024.01.27.577548, doi:10.1101/2024.01.27.577548. This article has 1 citations.
(ortega2024retargetingtargetdirectedmicrornadecay pages 1-2): Jesus A Ortega, Ziyan Liang, Junpeng Kenny Xu, and Eva Gottwein. Retargeting target-directed microrna-decay sites to highly expressed viral or cellular mirnas. Nucleic Acids Research, 52:14171-14183, Nov 2024. URL: https://doi.org/10.1093/nar/gkae1103, doi:10.1093/nar/gkae1103. This article has 4 citations and is from a highest quality peer-reviewed journal.
(ortega2024retargetingtargetdirectedmicrornadecay pages 2-4): Jesus A Ortega, Ziyan Liang, Junpeng Kenny Xu, and Eva Gottwein. Retargeting target-directed microrna-decay sites to highly expressed viral or cellular mirnas. Nucleic Acids Research, 52:14171-14183, Nov 2024. URL: https://doi.org/10.1093/nar/gkae1103, doi:10.1093/nar/gkae1103. This article has 4 citations and is from a highest quality peer-reviewed journal.
(ortega2024retargetingtargetdirectedmicrornadecay pages 10-11): Jesus A Ortega, Ziyan Liang, Junpeng Kenny Xu, and Eva Gottwein. Retargeting target-directed microrna-decay sites to highly expressed viral or cellular mirnas. Nucleic Acids Research, 52:14171-14183, Nov 2024. URL: https://doi.org/10.1093/nar/gkae1103, doi:10.1093/nar/gkae1103. This article has 4 citations and is from a highest quality peer-reviewed journal.
(han2020aubiquitinligase pages 1-2): Jaeil Han, Collette A. LaVigne, Benjamin T. Jones, He Zhang, Frank Gillett, and Joshua T. Mendell. A ubiquitin ligase mediates target-directed microrna decay independently of tailing and trimming. Science, Dec 2020. URL: https://doi.org/10.1126/science.abc9546, doi:10.1126/science.abc9546. This article has 246 citations and is from a highest quality peer-reviewed journal.
(han2020aubiquitinligase media 3f782238): Jaeil Han, Collette A. LaVigne, Benjamin T. Jones, He Zhang, Frank Gillett, and Joshua T. Mendell. A ubiquitin ligase mediates target-directed microrna decay independently of tailing and trimming. Science, Dec 2020. URL: https://doi.org/10.1126/science.abc9546, doi:10.1126/science.abc9546. This article has 246 citations and is from a highest quality peer-reviewed journal.
id: A7E2V4
gene_symbol: ZSWIM8
product_type: PROTEIN
status: COMPLETE
taxon:
id: NCBITaxon:9606
label: Homo sapiens
description: >-
ZSWIM8 encodes the substrate-recognition component of a Cullin-RING E3
ubiquitin ligase complex that recognizes Argonaute-miRNA complexes engaged
with highly complementary target RNAs and promotes target-directed miRNA
degradation. Human and metazoan evidence supports a CUL3/RBX1/ELOB/ELOC/ZSWIM8
complex, ubiquitin-proteasome-dependent AGO turnover, and an additional protein
quality-control role toward intrinsically disordered substrates such as DAB1.
alternative_products:
- name: '1'
id: A7E2V4-1
- name: '2'
id: A7E2V4-2
sequence_note: VSP_029590, VSP_029591
- name: '3'
id: A7E2V4-3
sequence_note: VSP_029586, VSP_029587, VSP_029590
- name: '4'
id: A7E2V4-4
sequence_note: VSP_029586
- name: '5'
id: A7E2V4-5
sequence_note: VSP_029590
existing_annotations:
- term:
id: GO:0031462
label: Cul2-RING ubiquitin ligase complex
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
Directionally correct as a Cullin-RING ligase annotation, but current
human experimental evidence supports ZSWIM8 as part of a CUL3-containing
CRL rather than a CUL2-RING ligase complex.
action: MODIFY
reason: >-
The ZSWIM8-ELOB-ELOC adaptor module was tested against CUL2, CUL5, and
CUL3 in the TDMD screen follow-up; CUL3, not CUL2, was required. The
existing IDA annotation to Cul3-RING ubiquitin ligase complex is the
appropriate replacement for the human protein.
proposed_replacement_terms:
- id: GO:0031463
label: Cul3-RING ubiquitin ligase complex
supported_by:
- reference_id: PMID:33184234
supporting_text: >-
In contrast, CUL3 knockout strongly repressed the reporter, suggesting
that the ZSWIM8 E3 ligase represents a CRL in which ZSWIM8-ELOB-ELOC
serve as substrate adapters for CUL3.
- term:
id: GO:0005829
label: cytosol
evidence_type: IEA
original_reference_id: GO_REF:0000044
review:
summary: >-
Cytosolic localization is consistent with UniProt and with ZSWIM8 acting
on AGO-miRNA complexes and cytosolic protein quality-control substrates.
action: ACCEPT
reason: >-
Although localization is not itself the catalytic function, cytosol is a
supported site for ZSWIM8 activity and is appropriate to retain.
supported_by:
- reference_id: file:human/ZSWIM8/ZSWIM8-uniprot.txt
supporting_text: 'SUBCELLULAR LOCATION: Cytoplasm, cytosol'
- term:
id: GO:0008270
label: zinc ion binding
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
ZSWIM8 contains a SWIM zinc-finger domain, so the IEA zinc-ion-binding
annotation is plausible as a domain-level molecular feature.
action: KEEP_AS_NON_CORE
reason: >-
The zinc-finger feature supports retention, but the biologically
informative core function is substrate-adaptor activity in a CRL rather
than generic zinc binding.
supported_by:
- reference_id: file:human/ZSWIM8/ZSWIM8-uniprot.txt
supporting_text: Znf_SWIM. (IPR007527)
- term:
id: GO:0016567
label: protein ubiquitination
evidence_type: IEA
original_reference_id: GO_REF:0000041
review:
summary: >-
Protein ubiquitination is supported by UniProt pathway annotation and by
experimental studies showing ZSWIM8 functions as the substrate adaptor of
a Cullin-RING E3 ubiquitin ligase.
action: ACCEPT
reason: >-
ZSWIM8 is not the catalytic RING subunit, but as the substrate-recognition
component of the CRL it directly enables ubiquitination of recruited
substrates.
supported_by:
- reference_id: PMID:33184234
supporting_text: >-
We identified a cullin-RING ubiquitin ligase (CRL), containing the
substrate adaptor ZSWIM8, that mediates TDMD.
- term:
id: GO:0006515
label: protein quality control for misfolded or incompletely synthesized proteins
evidence_type: IDA
original_reference_id: PMID:35989311
review:
summary: >-
ZSWIM8-dependent protein quality control is supported by knockout and
mechanistic work showing ZSWIM8 controls DAB1 quality in neurodevelopment.
action: ACCEPT
reason: >-
The annotation captures a direct substrate-quality-control role for the
ZSWIM8 ligase, distinct from but mechanistically related to its TDMD role.
supported_by:
- reference_id: PMID:35989311
supporting_text: >-
Mechanistic studies reveal that ZSWIM8 controls protein quality of
Disabled 1 (Dab1), a key signal molecule for brain development, thus
protecting the signaling strength of Dab1.
- term:
id: GO:0140958
label: target-directed miRNA degradation
evidence_type: IMP
original_reference_id: PMID:33184237
review:
summary: >-
This is a core ZSWIM8 biological process: loss-of-function studies show
that the ZSWIM8 CRL is required for target-directed miRNA degradation.
action: ACCEPT
reason: >-
The annotation is specific, experimentally supported, and captures the
best-characterized conserved process mediated by ZSWIM8.
supported_by:
- reference_id: PMID:33184237
supporting_text: >-
We found that this target-directed miRNA degradation (TDMD) required
the ZSWIM8 Cullin-RING E3 ubiquitin ligase.
- reference_id: file:human/ZSWIM8/ZSWIM8-deep-research-falcon.md
supporting_text: >-
ZSWIM8 is best-supported as the substrate-recognition subunit of a
Cullin-RING ubiquitin ligase (CRL) complex that executes TDMD by
targeting Argonaute proteins.
- term:
id: GO:0005829
label: cytosol
evidence_type: ISS
original_reference_id: GO_REF:0000024
review:
summary: >-
The sequence-similarity transfer to cytosol is consistent with UniProt
and with the cytosolic AGO-miRNA and protein quality-control contexts of
ZSWIM8.
action: ACCEPT
reason: >-
This duplicates the IEA localization evidence but is not contradicted by
experimental or curated summaries.
supported_by:
- reference_id: file:human/ZSWIM8/ZSWIM8-uniprot.txt
supporting_text: 'SUBCELLULAR LOCATION: Cytoplasm, cytosol'
- term:
id: GO:0016567
label: protein ubiquitination
evidence_type: IDA
original_reference_id: PMID:33184234
review:
summary: >-
Directly supported by the TDMD study identifying ZSWIM8 as the substrate
adaptor in a Cullin-RING ubiquitin ligase that acts on AGO-miRNA
complexes.
action: ACCEPT
reason: >-
ZSWIM8 recruits substrates to the ubiquitination machinery, making this
process annotation appropriate even though the catalytic RING activity is
supplied by the CRL complex.
supported_by:
- reference_id: PMID:33184234
supporting_text: >-
The ZSWIM8 CRL interacts with AGO proteins, promotes TDMD in a
tailing and trimming-independent manner, and regulates miRNA
expression in multiple cell types.
- term:
id: GO:0031463
label: Cul3-RING ubiquitin ligase complex
evidence_type: IDA
original_reference_id: PMID:33184234
review:
summary: >-
The Cul3-RING ubiquitin ligase complex annotation is the experimentally
supported complex context for human ZSWIM8.
action: ACCEPT
reason: >-
CUL3 was required in the CRISPR screen validation, while CUL2 and CUL5
knockouts were not, supporting CUL3 as the relevant cullin scaffold.
supported_by:
- reference_id: PMID:33184234
supporting_text: >-
In contrast, CUL3 knockout strongly repressed the reporter, suggesting
that the ZSWIM8 E3 ligase represents a CRL in which ZSWIM8-ELOB-ELOC
serve as substrate adapters for CUL3.
- term:
id: GO:0043161
label: proteasome-mediated ubiquitin-dependent protein catabolic process
evidence_type: IDA
original_reference_id: PMID:33184234
review:
summary: >-
ZSWIM8-mediated TDMD proceeds through ubiquitin-proteasome-dependent
turnover of AGO-containing complexes, so this process annotation is
supported.
action: ACCEPT
reason: >-
The annotation is broader than target-directed miRNA degradation but
accurately captures the proteasome-dependent degradation step mediated by
the ZSWIM8 CRL.
supported_by:
- reference_id: PMID:33184234
supporting_text: >-
These findings suggest a model in which the ZSWIM8 ubiquitin ligase
mediates TDMD by directing proteasomal decay of miRNA-containing
complexes engaged with highly complementary targets.
- term:
id: GO:1990756
label: ubiquitin-like ligase-substrate adaptor activity
evidence_type: IDA
original_reference_id: PMID:33184234
review:
summary: >-
This molecular-function term captures ZSWIM8's core role as the
substrate-recognition component of the TDMD Cullin-RING ubiquitin ligase.
action: ACCEPT
reason: >-
ZSWIM8 binds AGO proteins engaged with TDMD targets and recruits them to
the CUL3 CRL, which is exactly substrate-adaptor activity.
supported_by:
- reference_id: PMID:33184234
supporting_text: >-
We identified a cullin-RING ubiquitin ligase (CRL), containing the
substrate adaptor ZSWIM8, that mediates TDMD.
- term:
id: GO:1990756
label: ubiquitin-like ligase-substrate adaptor activity
evidence_type: IDA
original_reference_id: PMID:33184237
review:
summary: >-
Independent TDMD work also supports ZSWIM8 as the Cullin-RING ligase
adaptor required for target-directed miRNA degradation.
action: ACCEPT
reason: >-
The annotation is a core molecular function and is supported by
loss-of-function evidence linking the ZSWIM8 CRL to AGO proteolysis and
miRNA degradation.
supported_by:
- reference_id: PMID:33184237
supporting_text: >-
This and other findings support a mechanistic model of TDMD in which
target-directed proteolysis of AGO by the ubiquitin-proteasome pathway
exposes the miRNA for degradation.
- reference_id: PMID:33184234
supporting_text: >-
We identified a cullin-RING ubiquitin ligase (CRL), containing the
substrate adaptor ZSWIM8, that mediates TDMD.
- term:
id: GO:2000627
label: positive regulation of miRNA catabolic process
evidence_type: IDA
original_reference_id: PMID:33184234
review:
summary: >-
ZSWIM8 positively regulates miRNA catabolism by mediating TDMD of
miRNAs engaged with highly complementary target RNAs.
action: MODIFY
reason: >-
The term is directionally correct but less specific than the current GO
term for the experimentally demonstrated process, target-directed miRNA
degradation.
proposed_replacement_terms:
- id: GO:0140958
label: target-directed miRNA degradation
supported_by:
- reference_id: PMID:33184234
supporting_text: >-
The requirement for the ZSWIM8 ubquitin ligase in TDMD induced by two
unrelated substrates in different cell lines suggests that it
functions broadly in this pathway.
- term:
id: GO:2000627
label: positive regulation of miRNA catabolic process
evidence_type: IDA
original_reference_id: PMID:33184237
review:
summary: >-
The Bartel study supports the same positive regulatory role for ZSWIM8
in miRNA catabolism through the TDMD pathway.
action: MODIFY
reason: >-
The annotation should be replaced by the more specific TDMD process
term, which captures the tested biology without relying on a broad
parent-like regulation term.
proposed_replacement_terms:
- id: GO:0140958
label: target-directed miRNA degradation
supported_by:
- reference_id: PMID:33184237
supporting_text: >-
loss-of-function studies indicated that the ZSWIM8 Cullin-RING ligase
accelerates degradation of numerous miRNAs in cells of mammals, flies,
and nematodes
references:
- id: GO_REF:0000002
title: Gene Ontology annotation through association of InterPro records with GO terms
findings: []
- id: GO_REF:0000024
title: Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
findings: []
- id: GO_REF:0000033
title: Annotation inferences using phylogenetic trees
findings: []
- id: GO_REF:0000041
title: Gene Ontology annotation based on UniPathway vocabulary mapping
findings: []
- id: GO_REF:0000044
title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
findings: []
- id: PMID:33184234
title: A ubiquitin ligase mediates target-directed microRNA decay independently of tailing and trimming.
findings:
- statement: ZSWIM8 is the substrate adaptor of a Cullin-RING ubiquitin ligase that mediates TDMD.
supporting_text: >-
We identified a cullin-RING ubiquitin ligase (CRL), containing the
substrate adaptor ZSWIM8, that mediates TDMD.
- id: PMID:33184237
title: The ZSWIM8 ubiquitin ligase mediates target-directed microRNA degradation.
findings:
- statement: ZSWIM8 CRL activity is required for target-directed miRNA degradation.
supporting_text: >-
We found that this target-directed miRNA degradation (TDMD) required
the ZSWIM8 Cullin-RING E3 ubiquitin ligase.
- id: PMID:35989311
title: The ZSWIM8 ubiquitin ligase regulates neurodevelopment by guarding the protein quality of intrinsically disordered Dab1.
findings:
- statement: ZSWIM8 participates in protein quality control by regulating DAB1 quality.
supporting_text: >-
Mechanistic studies reveal that ZSWIM8 controls protein quality of
Disabled 1 (Dab1), a key signal molecule for brain development, thus
protecting the signaling strength of Dab1.
- id: file:human/ZSWIM8/ZSWIM8-uniprot.txt
title: UniProt text export for ZSWIM8 (A7E2V4)
findings:
- statement: UniProt describes ZSWIM8 as a substrate-recognition component of a TDMD-promoting E3 ligase.
supporting_text: >-
Substrate recognition component of a SCF-like E3 ubiquitin-protein
ligase complex that promotes target-directed microRNA degradation
- id: file:human/ZSWIM8/ZSWIM8-deep-research-falcon.md
title: Falcon deep research report for ZSWIM8
findings:
- statement: Falcon research supports ZSWIM8 as the core substrate-recognition subunit of the TDMD Cullin-RING ligase.
supporting_text: >-
ZSWIM8 is best-supported as the substrate-recognition subunit of a
Cullin-RING ubiquitin ligase (CRL) complex that executes TDMD by
targeting Argonaute proteins.
core_functions:
- description: >-
Substrate-adaptor activity in a CUL3 Cullin-RING ubiquitin ligase complex
that recognizes AGO-miRNA complexes engaged with TDMD targets and promotes
their ubiquitin-proteasome-dependent turnover.
molecular_function:
id: GO:1990756
label: ubiquitin-like ligase-substrate adaptor activity
directly_involved_in:
- id: GO:0140958
label: target-directed miRNA degradation
- id: GO:0016567
label: protein ubiquitination
- id: GO:0043161
label: proteasome-mediated ubiquitin-dependent protein catabolic process
locations:
- id: GO:0005829
label: cytosol
in_complex:
id: GO:0031463
label: Cul3-RING ubiquitin ligase complex
supported_by:
- reference_id: PMID:33184234
supporting_text: >-
The ZSWIM8 CRL interacts with AGO proteins, promotes TDMD in a tailing
and trimming-independent manner, and regulates miRNA expression in
multiple cell types.
- reference_id: PMID:33184237
supporting_text: >-
target-directed proteolysis of AGO by the ubiquitin-proteasome pathway
exposes the miRNA for degradation
- reference_id: file:human/ZSWIM8/ZSWIM8-deep-research-falcon.md
supporting_text: >-
ZSWIM8 is best-supported as the substrate-recognition subunit of a
Cullin-RING ubiquitin ligase (CRL) complex that executes TDMD by
targeting Argonaute proteins.
- description: >-
Protein quality control for misfolded or improperly phosphorylated
intrinsically disordered substrates, exemplified by DAB1 during mammalian
neurodevelopment.
molecular_function:
id: GO:1990756
label: ubiquitin-like ligase-substrate adaptor activity
directly_involved_in:
- id: GO:0006515
label: protein quality control for misfolded or incompletely synthesized proteins
locations:
- id: GO:0005829
label: cytosol
supported_by:
- reference_id: PMID:35989311
supporting_text: >-
ZSWIM8 specifically recognizes IDRs of Dab1 through a "disorder targets
misorder" mechanism and eliminates misfolded Dab1 that cannot be
properly phosphorylated.
proposed_new_terms: []
suggested_questions:
- question: Which endogenous human TDMD targets account for the strongest ZSWIM8-dependent miRNA half-life changes across cell types?
- question: Does ZSWIM8 use the same substrate-recognition surface for AGO-miRNA complexes and intrinsically disordered protein quality-control substrates such as DAB1?
- question: Is the Cul2-RING IBA annotation a legacy transfer from non-human EBAX systems that should be corrected upstream to Cul3-RING ubiquitin ligase complex?
suggested_experiments:
- description: Endogenous-tag ZSWIM8, CUL3, ELOB, and ELOC in human cells and perform target-triggered AGO proximity labeling with and without TDMD-inducing transcripts.
experiment_type: proteomics/proximity labeling
hypothesis: ZSWIM8 recruits AGO-miRNA complexes to a CUL3 CRL specifically when TDMD target pairing exposes the AGO-bound miRNA.
- description: Mutational separation of ZSWIM8 SWIM/TPR/C-terminal regions followed by rescue assays for miR-7 TDMD and DAB1 protein quality control.
experiment_type: structure-function rescue
hypothesis: Distinct substrate-recognition modules contribute to AGO-dependent TDMD and DAB1 quality-control functions.
- description: Comparative CRL assembly assays testing CUL2, CUL3, and CUL5 binding to human ZSWIM8-ELOB-ELOC under endogenous expression conditions.
experiment_type: biochemical reconstitution/co-immunoprecipitation
hypothesis: Human ZSWIM8 preferentially forms a functional CUL3-RING ubiquitin ligase complex rather than a Cul2-RING complex.