Functional-annotation report: *Arabidopsis thaliana* DRS1 (At1g80710; UniProt Q9SAI7) Falcon Edison Scientific Literature 13 citations 1 artifacts 2026-09-10T14:55:36.958040

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Functional-annotation report: Arabidopsis thaliana DRS1 (At1g80710; UniProt Q9SAI7)

Executive conclusion

The gene symbol DRS1 is ambiguous across biology, and the literature retrieved does not provide a target-specific mechanistic study for the protein defined here. For this report, the verified target is strictly Q9SAI7 = At1g80710 = DRS1/DROUGHT SENSITIVE 1 = F23A5.6/F23A5_6 from Arabidopsis thaliana, based on the supplied UniProt record. It is annotated as WD repeat-containing protein 76, belonging to the WD-repeat DDB2/WDR76 family, with multiple WD40-related InterPro signatures.

Accordingly, the strongest defensible functional annotation is: DRS1 is a predicted nonenzymatic WD40-repeat interaction protein, probably forming a β-propeller scaffold for assembly or regulation of a protein complex. No catalytic reaction, transported substrate, specific ligand, protein partner, pathway, cellular compartment, or quantitative mutant phenotype could be established for At1g80710 from the retrieved primary literature. Its exact molecular function therefore remains uncharacterized.

1. Mandatory identity verification

Correct identifiers

Searches using the accession, locus, symbol, full synonym, ORF names, family, localization/function terms, and a 2023–2024 date restriction found no publication explicitly characterizing Q9SAI7/At1g80710. Thus, the gene symbol is usable only when coupled to the accession, locus, and organism.

Exclusion of deceptively similar Arabidopsis proteins

The best-retrieved mechanistic paper concerned ABD1, an Arabidopsis WD40/DCAF protein involved in ABA signaling. ABD1 is explicitly At4g38480, not At1g80710. Its demonstrated interaction with DDB1 and ABI5, nuclear activity, control of ABI5 proteasomal degradation, ABA/NaCl hypersensitivity, reduced water loss, and enhanced drought tolerance must not be assigned to DRS1 (Seo et al., published February 2014; https://doi.org/10.1105/tpc.113.119974). (seo2014abd1isanarabidopsisdcaf pages 2-4, seo2014abd1isanarabidopsisdcaf pages 10-11, seo2014abd1isanarabidopsisdcaf pages 14-15, seo2014abd1isanarabidopsisdcaf pages 1-2)

Similarly, XIW1 is a separately characterized Arabidopsis WD40 protein whose nucleocytoplasmic trafficking and interactions with XPO1 and ABI5 regulate ABA responses. These results illustrate possible WD40-protein mechanisms but provide no evidence about At1g80710 (Xu et al., published December 2019; https://doi.org/10.1016/j.molp.2019.07.001). (xu2019nucleocytoplasmictraffickingof pages 2-4, xu2019nucleocytoplasmictraffickingof pages 1-2)

2. Key concepts and current functional interpretation

WD40-repeat architecture

WD40 repeats are typically approximately 40 residues long and assemble into propeller-like structures. Their exposed surfaces and grooves support interactions with proteins or other ligands, allowing many WD40 proteins to organize multiprotein complexes. Approximately 237 WD40-family proteins have been identified in Arabidopsis, emphasizing that this is a large and functionally diverse family rather than a group with one conserved pathway (Sharma and Pandey, published January 2016; https://doi.org/10.3389/fpls.2015.01218). (sharma2016expansionandfunction pages 1-2, sharma2016expansionandfunction pages 2-3)

This architecture supports classifying Q9SAI7 provisionally as an adapter or scaffold, not as an enzyme or transporter. However, a WD40 domain predicts an interaction-oriented structural framework—not the identity of the interacting partners, the regulated pathway, or the cellular location. Full-length sequence context, accessory motifs, localization, genetics, and biochemical interaction data are needed for a specific assignment. (sharma2016expansionandfunction pages 1-2, sharma2016expansionandfunction pages 2-3, sharma2016expansionandfunction pages 13-14)

Meaning of the DDB2/WDR76-family annotation

The supplied UniProt annotation places Q9SAI7 in the DDB2/WDR76 family and reports WD40 and DNA-damage-binding-type WD-repeat signatures. This alignment is internally coherent: DDB2/WDR76-family proteins are WD-repeat proteins, and the listed InterPro signatures all support a WD40-repeat/β-propeller-type architecture.

Nevertheless, family naming must not be converted directly into a pathway annotation. In particular, the available target-specific evidence does not establish that Arabidopsis DRS1 binds damaged DNA, participates in nucleotide-excision repair, serves as a DDB1–CUL4 substrate receptor, or controls ubiquitination. Those are experimentally testable hypotheses, not currently supported conclusions for At1g80710.

Annotation question Conclusion Evidence type/strength Caveat
Identity DRS1 = At1g80710 = UniProt Q9SAI7; synonyms include DROUGHT SENSITIVE 1 and ORF names F23A5.6/F23A5_6. User-supplied UniProt record; direct database identity. Exact-identifier searches found no target-specific paper, including from 2023–2024.
Organism The target is Arabidopsis thaliana (mouse-ear cress). User-supplied UniProt record; direct database identity. Findings for similarly named genes in other organisms must not be transferred.
Family and domains Annotated as WD repeat-containing protein 76 in the DDB2/WDR76 family, with WD40-repeat and DNA-damage-binding-type WD-repeat signatures. User-supplied UniProt/InterPro annotations; computational family/domain evidence. Family membership does not establish the target’s pathway, partners, substrates, or phenotype.
Structural role Q9SAI7 plausibly forms a β-propeller interaction scaffold that helps assemble protein complexes. WD40 repeats are approximately 40 residues long and commonly form propeller-like interaction surfaces; about 237 WD40 proteins have been identified in Arabidopsis. (sharma2016expansionandfunction pages 1-2, sharma2016expansionandfunction pages 2-3) Moderate family-level structural inference; no target-specific experimental evidence. The full-length Q9SAI7 structure and scaffold function have not been experimentally demonstrated in the retrieved literature.
Catalytic or transport activity No enzyme reaction, catalytic substrate specificity, transported substrate, or transport mechanism is established. Its repeat architecture favors a nonenzymatic adapter/scaffold interpretation. (sharma2016expansionandfunction pages 1-2, sharma2016expansionandfunction pages 2-3) Absence of target-specific biochemical evidence plus cautious domain-based inference. A WD40 domain alone cannot exclude an unrecognized biochemical activity elsewhere in the protein.
Binding partners No experimentally validated Q9SAI7/At1g80710 binding partner was found. No target-specific interaction evidence retrieved. Interactions of other WD40 proteins cannot be assigned to DRS1.
Subcellular localization Unknown. No target-specific microscopy, fractionation, or localization study was found. No direct target-specific evidence. Localization of other WD40 proteins does not predict Q9SAI7’s location reliably.
Signaling or biochemical pathway No pathway assignment is established. A role in a multiprotein regulatory complex is plausible but unspecified. Weak family-level inference only. The DDB2/WDR76-family annotation alone cannot establish involvement in DNA repair, ubiquitination, ABA signaling, or another pathway.
Drought/ABA phenotype The synonym DROUGHT SENSITIVE 1 suggests a phenotype-based designation, but the retrieved literature did not establish a drought mechanism, ABA role, or quantitative phenotype for At1g80710. Nomenclature from the user-supplied UniProt record; no retrieved target-specific primary evidence. The name must not be treated as proof of pathway membership or molecular mechanism.
Exclusion of ABD1 ABD1 is At4g38480, not At1g80710. ABD1’s CUL4–DDB1/ABI5 mechanism, nuclear interaction, ABA phenotypes, and drought tolerance therefore do not annotate DRS1. (seo2014abd1isanarabidopsisdcaf pages 2-4, seo2014abd1isanarabidopsisdcaf pages 14-15, seo2014abd1isanarabidopsisdcaf pages 1-2) Strong direct locus-level exclusion from primary literature. Shared WD40/DCAF-like features do not demonstrate an equivalent function.
Exclusion of XIW1 XIW1 is a separately studied Arabidopsis WD40 protein. Its XPO1/ABI5 interactions, nucleocytoplasmic trafficking, and ABA-response functions must not be transferred to At1g80710. (xu2019nucleocytoplasmictraffickingof pages 2-4, xu2019nucleocytoplasmictraffickingof pages 1-2) Strong protein-specific distinction; XIW1 findings are direct only for XIW1. Functional analogy is hypothesis-generating rather than annotation evidence.
Current research status Literature is limited for this specific protein: no target-specific 2023–2024 publication was found in the searches performed. Repeated searches by accession, locus, symbol, synonym, ORF, family, and publication date. “No paper found” describes the retrieved search corpus and does not exclude unpublished or unindexed evidence.

Table: This table separates direct identity and domain annotations for Arabidopsis DRS1 from general WD40-family inference and findings about different proteins. It highlights the unresolved functional questions and lack of target-specific 2023–2024 literature in the searches performed.

3. Primary molecular function

Best-supported assignment

The probable primary role is noncatalytic molecular scaffolding or partner recruitment through a WD40 β-propeller. Plant WD40 proteins are well documented as components of transcriptional, signaling, protein-stability, developmental, and stress-response complexes. For example, TTG1 acts in a MYB–bHLH–WD40 regulatory complex, whereas other WD40 proteins participate in CUL4–DDB1 ubiquitin-ligase or chromatin-regulatory assemblies. These examples establish the functional versatility of the fold, not the identity of the DRS1 complex. (xu2019nucleocytoplasmictraffickingof pages 13-13, sharma2016expansionandfunction pages 10-11)

Catalysis, substrate specificity, and transport

There is no evidence that Q9SAI7 is an enzyme; therefore, no reaction, catalytic mechanism, cofactor, or substrate specificity can presently be assigned. There is likewise no evidence that it is a transporter, and no transported substrate has been identified. The domain architecture instead favors an adapter/scaffold interpretation, although this remains inferential until direct biochemical work is performed. (sharma2016expansionandfunction pages 1-2, sharma2016expansionandfunction pages 2-3)

Interacting partners

No experimentally validated binding partner for Q9SAI7/At1g80710 was identified. DDB1, CUL4, ABI5, XPO1, and other partners reported for distinct WD40 proteins must not be entered as DRS1 interactors. The most informative initial experiments would be affinity-purification mass spectrometry or proximity labeling from a functional, native-promoter DRS1 fusion, followed by reciprocal co-immunoprecipitation and genetic validation.

4. Cellular localization

The intracellular location at which DRS1 functions is unknown. No target-specific fluorescent-protein localization, immunocytochemistry, biochemical fractionation, organellar proteomics, or nuclear-import/export study was retrieved.

WD40 proteins can be nuclear, cytoplasmic, organelle-associated, or dynamically distributed. XIW1, for example, occurs in both the cytoplasm and nucleus, but that observation is protein-specific and cannot be transferred to DRS1. (xu2019nucleocytoplasmictraffickingof pages 2-4, xu2019nucleocytoplasmictraffickingof pages 1-2)

Consequently, assigning DRS1 to the nucleus merely from the DDB2/WDR76-family label would be premature. A native-promoter fluorescent fusion that rescues a verified drs1 phenotype would provide substantially stronger localization evidence than transient overexpression alone.

5. Biological processes and pathways

Drought and ABA signaling

The synonym DROUGHT SENSITIVE 1 suggests that the locus may have received a phenotype-based designation connected to water deficit. However, the retrieved literature did not provide the originating mutant study, allelic evidence, complementation, physiological measurements, or a molecular mechanism for At1g80710. The name by itself is therefore insufficient to conclude that DRS1 is an ABA-pathway component.

This distinction is important because several unrelated Arabidopsis WD40 proteins do regulate ABA or drought responses by different mechanisms. ABD1 acts through CUL4–DDB1 and ABI5 turnover, while XIW1 regulates ABI5 stability and trafficking. Their mechanistic diversity shows why “WD40 protein associated with drought” is not a transferable annotation. (seo2014abd1isanarabidopsisdcaf pages 2-4, seo2014abd1isanarabidopsisdcaf pages 9-10, seo2014abd1isanarabidopsisdcaf pages 1-2, xu2019nucleocytoplasmictraffickingof pages 2-4)

DNA damage and ubiquitin-dependent regulation

The DDB2/WDR76-family annotation makes roles in DNA-associated or protein-complex regulation plausible hypotheses. Yet no direct evidence was found for DRS1 in DNA-damage recognition, repair, chromatin regulation, or ubiquitin-dependent proteolysis. ABD1 demonstrates that an Arabidopsis WD40/DCAF can bind DDB1 and act as a CUL4 substrate receptor, but ABD1 is a different locus and cannot establish the same activity for DRS1. (seo2014abd1isanarabidopsisdcaf pages 2-4, seo2014abd1isanarabidopsisdcaf pages 14-15)

Current pathway annotation

At present, the appropriate pathway designation is unresolved. The most that can be said is that DRS1 probably participates in a multiprotein regulatory complex, with drought/stress involvement suggested by nomenclature but not mechanistically established in the evidence retrieved.

6. Recent developments, applications, and quantitative evidence

2023–2024 literature

No target-specific publication from 2023 or 2024 was found for “At1g80710,” “Q9SAI7,” “F23A5.6,” or the exact Arabidopsis DRS1 identity. Recent work on other Arabidopsis WD40 proteins cannot remedy that evidence gap. Therefore, there is no defensible 2023–2024 update on DRS1 mechanism, localization, interactors, structure, or phenotype.

Real-world applications

No crop-engineering, breeding, diagnostic, biotechnology, or field implementation specifically involving At1g80710 was identified. DRS1 may eventually be relevant to drought-resilience research, but translational use would require at minimum:

  1. independently validated loss- and gain-of-function alleles;
  2. complementation proving locus–phenotype causality;
  3. quantitative drought assays under controlled and field-like conditions;
  4. determination of growth or yield penalties;
  5. identification of the molecular complex and pathway; and
  6. conservation and functional validation of orthologs in crops.

Relevant statistics

The only reliable quantitative family-level statistic retrieved is the estimate of approximately 237 WD40 proteins in Arabidopsis and nearly 200 in rice. This large family size underscores the risk of inferring specific function from the domain alone. (sharma2016expansionandfunction pages 1-2)

No trustworthy target-specific values were found for expression changes, survival, water loss, stomatal conductance, protein abundance, interaction affinity, mutant effect size, or structural confidence. Quantitative values reported for ABD1, XIW1, or other WD40 proteins would be irrelevant to Q9SAI7.

7. Expert assessment and evidence ranking

High confidence: the supplied identifier mapping, organism, WD-repeat annotation, and DDB2/WDR76-family placement.

Moderate confidence: Q9SAI7 likely adopts a WD40 β-propeller and functions as a protein-interaction scaffold. This is a structure/family-based inference supported by established WD40 biology. (sharma2016expansionandfunction pages 1-2, sharma2016expansionandfunction pages 2-3)

Low confidence/hypothesis only: participation in drought response, ABA signaling, DNA-damage biology, chromatin regulation, or CUL4–DDB1-mediated ubiquitination.

Unknown: exact complex, binding partners, biochemical pathway, localization, regulated substrate, molecular phenotype, tissue-specific role, and translational utility.

The most decisive next steps are: (i) verify independent drs1 alleles and rescue with genomic At1g80710; (ii) quantify drought responses alongside ABA sensitivity, stomatal conductance, water-loss rate, osmotic controls, and developmental covariates; (iii) localize a functional native-promoter DRS1 fusion; (iv) identify partners by affinity purification/proximity labeling; (v) test candidate DDB1/CUL4 association only after unbiased interaction analysis; and (vi) determine a full-length structure experimentally or compare a high-confidence predicted model with plant WDR76/DDB2 homologs. These experiments would distinguish a genuine drought-signaling component from a broader protein-homeostasis, chromatin, or DNA-associated scaffold.

Overall conclusion

The gene symbol “DRS1” is ambiguous and literature is limited for this specific protein. For the correctly identified Arabidopsis target Q9SAI7/At1g80710, available annotation supports a WD40-repeat DDB2/WDR76-family protein whose most likely broad role is nonenzymatic assembly of a protein complex. There is presently insufficient target-specific evidence to state which complex, pathway, or cellular compartment is involved. The drought-related name is biologically suggestive but cannot substitute for direct genetic and mechanistic evidence, and findings for ABD1, XIW1, HOS15, or similarly named genes must not be transferred to DRS1.

References

  1. (seo2014abd1isanarabidopsisdcaf pages 2-4): Kyoung-In Seo, Jae-Hoon Lee, Cynthia D. Nezames, Shangwei Zhong, Eunyoung Song, Myung-Ok Byun, and Xing Wang Deng. Abd1 is anarabidopsisdcaf substrate receptor for cul4-ddb1–based e3 ligases that acts as a negative regulator of abscisic acid signaling. The Plant Cell, 26(2):695-711, Feb 2014. URL: https://doi.org/10.1105/tpc.113.119974, doi:10.1105/tpc.113.119974. This article has 202 citations.

  2. (seo2014abd1isanarabidopsisdcaf pages 10-11): Kyoung-In Seo, Jae-Hoon Lee, Cynthia D. Nezames, Shangwei Zhong, Eunyoung Song, Myung-Ok Byun, and Xing Wang Deng. Abd1 is anarabidopsisdcaf substrate receptor for cul4-ddb1–based e3 ligases that acts as a negative regulator of abscisic acid signaling. The Plant Cell, 26(2):695-711, Feb 2014. URL: https://doi.org/10.1105/tpc.113.119974, doi:10.1105/tpc.113.119974. This article has 202 citations.

  3. (seo2014abd1isanarabidopsisdcaf pages 14-15): Kyoung-In Seo, Jae-Hoon Lee, Cynthia D. Nezames, Shangwei Zhong, Eunyoung Song, Myung-Ok Byun, and Xing Wang Deng. Abd1 is anarabidopsisdcaf substrate receptor for cul4-ddb1–based e3 ligases that acts as a negative regulator of abscisic acid signaling. The Plant Cell, 26(2):695-711, Feb 2014. URL: https://doi.org/10.1105/tpc.113.119974, doi:10.1105/tpc.113.119974. This article has 202 citations.

  4. (seo2014abd1isanarabidopsisdcaf pages 1-2): Kyoung-In Seo, Jae-Hoon Lee, Cynthia D. Nezames, Shangwei Zhong, Eunyoung Song, Myung-Ok Byun, and Xing Wang Deng. Abd1 is anarabidopsisdcaf substrate receptor for cul4-ddb1–based e3 ligases that acts as a negative regulator of abscisic acid signaling. The Plant Cell, 26(2):695-711, Feb 2014. URL: https://doi.org/10.1105/tpc.113.119974, doi:10.1105/tpc.113.119974. This article has 202 citations.

  5. (xu2019nucleocytoplasmictraffickingof pages 2-4): Xuezhong Xu, Wang Wan, Guobin Jiang, Yue Xi, Haijian Huang, Jiajia Cai, Yanan Chang, Cheng-Guo Duan, Satendra K. Mangrauthia, Xinxiang Peng, Jian-Kang Zhu, and Guohui Zhu. Nucleocytoplasmic trafficking of the arabidopsis wd40 repeat protein xiw1 regulates abi5 stability and abscisic acid responses. Molecular plant, 12:1598-1611, Dec 2019. URL: https://doi.org/10.1016/j.molp.2019.07.001, doi:10.1016/j.molp.2019.07.001. This article has 94 citations and is from a highest quality peer-reviewed journal.

  6. (xu2019nucleocytoplasmictraffickingof pages 1-2): Xuezhong Xu, Wang Wan, Guobin Jiang, Yue Xi, Haijian Huang, Jiajia Cai, Yanan Chang, Cheng-Guo Duan, Satendra K. Mangrauthia, Xinxiang Peng, Jian-Kang Zhu, and Guohui Zhu. Nucleocytoplasmic trafficking of the arabidopsis wd40 repeat protein xiw1 regulates abi5 stability and abscisic acid responses. Molecular plant, 12:1598-1611, Dec 2019. URL: https://doi.org/10.1016/j.molp.2019.07.001, doi:10.1016/j.molp.2019.07.001. This article has 94 citations and is from a highest quality peer-reviewed journal.

  7. (sharma2016expansionandfunction pages 1-2): Manisha Sharma and Girdhar K. Pandey. Expansion and function of repeat domain proteins during stress and development in plants. Frontiers in Plant Science, Jan 2016. URL: https://doi.org/10.3389/fpls.2015.01218, doi:10.3389/fpls.2015.01218. This article has 231 citations.

  8. (sharma2016expansionandfunction pages 2-3): Manisha Sharma and Girdhar K. Pandey. Expansion and function of repeat domain proteins during stress and development in plants. Frontiers in Plant Science, Jan 2016. URL: https://doi.org/10.3389/fpls.2015.01218, doi:10.3389/fpls.2015.01218. This article has 231 citations.

  9. (sharma2016expansionandfunction pages 13-14): Manisha Sharma and Girdhar K. Pandey. Expansion and function of repeat domain proteins during stress and development in plants. Frontiers in Plant Science, Jan 2016. URL: https://doi.org/10.3389/fpls.2015.01218, doi:10.3389/fpls.2015.01218. This article has 231 citations.

  10. (xu2019nucleocytoplasmictraffickingof pages 13-13): Xuezhong Xu, Wang Wan, Guobin Jiang, Yue Xi, Haijian Huang, Jiajia Cai, Yanan Chang, Cheng-Guo Duan, Satendra K. Mangrauthia, Xinxiang Peng, Jian-Kang Zhu, and Guohui Zhu. Nucleocytoplasmic trafficking of the arabidopsis wd40 repeat protein xiw1 regulates abi5 stability and abscisic acid responses. Molecular plant, 12:1598-1611, Dec 2019. URL: https://doi.org/10.1016/j.molp.2019.07.001, doi:10.1016/j.molp.2019.07.001. This article has 94 citations and is from a highest quality peer-reviewed journal.

  11. (sharma2016expansionandfunction pages 10-11): Manisha Sharma and Girdhar K. Pandey. Expansion and function of repeat domain proteins during stress and development in plants. Frontiers in Plant Science, Jan 2016. URL: https://doi.org/10.3389/fpls.2015.01218, doi:10.3389/fpls.2015.01218. This article has 231 citations.

  12. (seo2014abd1isanarabidopsisdcaf pages 9-10): Kyoung-In Seo, Jae-Hoon Lee, Cynthia D. Nezames, Shangwei Zhong, Eunyoung Song, Myung-Ok Byun, and Xing Wang Deng. Abd1 is anarabidopsisdcaf substrate receptor for cul4-ddb1–based e3 ligases that acts as a negative regulator of abscisic acid signaling. The Plant Cell, 26(2):695-711, Feb 2014. URL: https://doi.org/10.1105/tpc.113.119974, doi:10.1105/tpc.113.119974. This article has 202 citations.

Artifacts

Citations

  1. sharma2016expansionandfunction pages 1-2
  2. xu2019nucleocytoplasmictraffickingof pages 2-4
  3. xu2019nucleocytoplasmictraffickingof pages 1-2
  4. sharma2016expansionandfunction pages 2-3
  5. sharma2016expansionandfunction pages 13-14
  6. xu2019nucleocytoplasmictraffickingof pages 13-13
  7. sharma2016expansionandfunction pages 10-11
  8. https://doi.org/10.1105/tpc.113.119974
  9. https://doi.org/10.1016/j.molp.2019.07.001
  10. https://doi.org/10.3389/fpls.2015.01218
  11. https://doi.org/10.1105/tpc.113.119974,
  12. https://doi.org/10.1016/j.molp.2019.07.001,
  13. https://doi.org/10.3389/fpls.2015.01218,