Research report: putative *Schizosaccharomyces pombe* **asr1** / O94400 Falcon Edison Scientific Literature 8 citations 1 artifacts 2026-09-08T19:11:42.820245

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.

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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.

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Research report: putative Schizosaccharomyces pombe asr1 / O94400

Executive conclusion

The gene symbol “asr1” is ambiguous, and literature is extremely limited for this specific protein. The supplied UniProt record identifies the target unambiguously at the sequence-record level as O94400, ORF SPCC126.07c, from Schizosaccharomyces pombe strain 972/ATCC 24843, with the descriptive name “PHD and RING finger domain-containing protein C126.07c.” However, the literature searches performed here did not independently confirm asr1 as the curated gene symbol for O94400.

No primary publication was found that directly establishes O94400’s molecular function, biochemical substrate, pathway, interaction partners, mutant phenotype, or subcellular localization. Accordingly, it would be unsafe to assign functions reported for similarly named proteins in budding or methylotrophic yeasts. The defensible annotation is therefore: a poorly characterized, predicted PHD/RING-like zinc-binding protein whose precise function and cellular location remain unknown.

Annotation/question Best-supported conclusion Evidence type Confidence
Identity The research target is UniProt O94400, ORF SPCC126.07c, from Schizosaccharomyces pombe strain 972/ATCC 24843. The supplied record describes it as “PHD and RING finger domain-containing protein C126.07c”; asr1 was not independently verified as its curated gene symbol. User-supplied UniProt metadata; exact-identifier literature searches Moderate
Domain architecture The supplied InterPro annotations identify PHRF1/Atg35, PHD-type zinc-finger, and broader FYVE/PHD zinc-finger signatures. These indicate a cysteine/histidine-rich zinc-binding protein but do not by themselves establish histone recognition, phosphoinositide binding, ubiquitin-ligase activity, or autophagy function. Computational domain annotation supplied with the query Moderate for domain presence; low for inferred function
Primary molecular function Unknown. No directly relevant biochemical study was found establishing catalytic activity, binding partners, substrates, or structural-adaptor function for O94400/SPCC126.07c. Negative result from exact-accession, ORF-name, organism, alias, and domain-based literature searches Low/unknown
Pathway Unknown. Assignment to autophagy, pexophagy, chromatin regulation, transcription, or ubiquitin signaling is unsupported without direct evidence or validated orthology. Evidence-gap assessment Low/unknown
Localization Unknown. No O94400-specific microscopy, fractionation, or curated experimental localization evidence was retrieved. Evidence-gap assessment Low/unknown
Confusing Pichia Atg35 literature Atg35 in Pichia pastoris (now commonly Komagataella phaffii) is reported as a micropexophagy-specific regulator/marker recruited in an Atg17-dependent manner to a punctate perinuclear structure associated with the micropexophagic apparatus. The cited literature provides no sequence or orthology evidence connecting that protein to S. pombe O94400, so this function and localization must not be transferred (klionsky2011acomprehensiveglossary pages 11-12, klionsky2011acomprehensiveglossary pages 12-14, klionsky2011acomprehensiveglossary pages 17-18). Organism-specific published evidence plus explicit absence of an O94400 linkage High for Pichia Atg35; very low for transfer to O94400
Confusing S. cerevisiae Asr1 literature Searches encountered a distinct budding-yeast Asr1 discussed in RNA-polymerase-II regulation. Because it is from another organism and no validated orthology to SPCC126.07c was found, its transcription-related function must not be assigned to O94400. Same-symbol literature-screening result; no validated orthology High that transfer is unsafe
2023–2024 developments No directly relevant 2023–2024 primary study or review was found for O94400/SPCC126.07c. Consequently, there are no supported recent functional developments, implementations, or quantitative statistics specific to this protein. Date-restricted and exact-identifier literature searches Moderate

Table: This table separates what is known about the S. pombe protein from domain-based hypotheses and similarly named proteins in other yeasts. It highlights that molecular function, pathway, and localization remain experimentally unresolved.

1. Identity verification and nomenclature

Verified target

The intended target, based on the supplied UniProt information, is:

This identity must be maintained throughout annotation. In particular, the protein should not be conflated with a different Asr1 studied in Saccharomyces cerevisiae or with Atg35 from Pichia pastoris/Komagataella phaffii.

Critical same-name conflict: Pichia Atg35

The retrieved autophagy literature identifies Atg35 specifically as a protein of the methylotrophic yeast Pichia pastoris, now commonly called Komagataella phaffii. It is described as a micropexophagy-specific regulator or marker of a punctate perinuclear structure, with recruitment dependent on Atg17; the structure may correspond to the phagophore assembly site. Crucially, this literature provides no sequence, orthology, or nomenclature evidence linking that Atg35 to S. pombe O94400 (klionsky2011acomprehensiveglossary pages 11-12, klionsky2011acomprehensiveglossary pages 12-14, klionsky2011acomprehensiveglossary pages 17-18).

Therefore, perinuclear localization, Atg17 dependence, and micropexophagy function cannot be transferred to O94400. The relevant review was published in November 2011: Klionsky et al., Autophagy 7:1273–1294, DOI 10.4161/auto.7.11.17661 (klionsky2011acomprehensiveglossary pages 11-12, klionsky2011acomprehensiveglossary pages 17-18).

2. Domain architecture and present functional understanding

The supplied InterPro annotations are:

These overlapping annotations support the presence of a cysteine/histidine-rich zinc-binding fold related to PHD/RING/FYVE-like domains. They do not establish a protein family assignment at the level needed to infer a precise biological role.

PHD fingers frequently function as protein- or chromatin-binding modules, and some recognize modified histone tails. RING-like zinc fingers frequently occur in ubiquitin E3 ligases, whereas canonical FYVE domains can bind phosphatidylinositol-3-phosphate on endomembranes. Nevertheless, these are general possibilities, not O94400-specific conclusions. Closely related zinc-coordinating folds can have different ligands and functions, and motif/superfamily matching alone does not demonstrate:

  1. histone-mark recognition;
  2. phosphoinositide binding;
  3. ubiquitin E3-ligase activity;
  4. autophagy or pexophagy participation; or
  5. nuclear or membrane localization.

Consequently, O94400 should presently be regarded as a predicted zinc-finger interaction protein, not as a confirmed enzyme, lipid-binding factor, chromatin reader, E3 ligase, or autophagy protein.

3. Primary molecular function

What is established

No directly relevant biochemical characterization was retrieved. There is no supported catalytic reaction, substrate specificity, ligand, binding partner, or macromolecular complex assignment for O94400/SPCC126.07c.

Best functional interpretation

The domain architecture suggests that the protein is more likely to act as an interaction module, adapter, or regulatory factor than as a conventional metabolic enzyme or transporter. However, whether it binds proteins, chromatin, ubiquitin-system components, or membranes remains unresolved.

Any annotation more specific than “PHD/RING-like zinc-finger protein of unknown function” should therefore be labeled computationally inferred and low confidence until validated experimentally.

4. Biological processes and pathways

No pathway assignment specific to O94400 could be substantiated. In particular:

Thus, no signaling or biochemical pathway should currently be entered as experimentally established.

5. Subcellular localization

The localization of O94400 is unknown based on the retrieved evidence. No direct fluorescence microscopy, immunolocalization, cell-fractionation, proximity-labeling, or organelle-proteomics result specific to SPCC126.07c was found.

The perinuclear localization reported for Pichia Atg35 is organism- and protein-specific. In that system, Atg35 marks a punctate perinuclear structure associated with micropexophagy, and recruitment depends on Atg17; the source explicitly does not establish equivalence to S. pombe O94400 (klionsky2011acomprehensiveglossary pages 11-12, klionsky2011acomprehensiveglossary pages 12-14).

6. Recent developments, applications, and quantitative evidence

2023–2024 research

Exact-accession, ORF-name, alias, organism, and domain-based searches did not retrieve a directly relevant 2023–2024 primary study or authoritative review for O94400/SPCC126.07c. Therefore, there are no supported recent mechanistic developments specific to this protein.

Applications and real-world implementation

No biotechnology, industrial, diagnostic, therapeutic, or other real-world application was identified for O94400. Given that its primary function is unresolved, claims of application would be premature.

Statistics and recent datasets

No O94400-specific quantitative measurements—such as enzymatic constants, binding affinities, expression fold changes, localization frequencies, genetic-interaction effect sizes, or deletion-phenotype penetrance—were found. The lack of numerical results is itself important: there is currently no quantitative basis for assigning substrate specificity, pathway strength, or compartmental enrichment.

7. Evidence assessment and expert interpretation

The authoritative interpretation is conservative:

  1. High confidence: O94400/SPCC126.07c is the intended S. pombe sequence record, based on the identity supplied in the query.
  2. Moderate confidence: it contains a PHD/RING/FYVE-like zinc-binding region, based on multiple overlapping InterPro signatures supplied with the record.
  3. Low confidence: it may be an interaction or regulatory protein associated with chromatin, ubiquitin signaling, or membranes.
  4. Unsupported: specific E3-ligase activity, histone recognition, phosphoinositide binding, autophagy function, pexophagy function, or perinuclear localization.

The strongest literature-based warning is that the well-defined Atg35 phenotype belongs to P. pastoris: micropexophagy-specific apparatus regulation and Atg17-dependent recruitment to a punctate perinuclear structure (klionsky2011acomprehensiveglossary pages 11-12, klionsky2011acomprehensiveglossary pages 12-14, klionsky2011acomprehensiveglossary pages 17-18). Without reciprocal sequence-comparison, conserved-synteny, phylogenetic, or functional-complementation evidence, that biology must not be projected onto O94400.

8. Experiments needed for functional annotation

The highest-value next steps would be:

  1. Nomenclature and orthology audit: confirm whether asr1 is a current PomBase synonym and test reciprocal orthology to Pichia Atg35 and S. cerevisiae Asr1 using full-length sequence phylogeny and conserved synteny.
  2. Endogenous localization: tag SPCC126.07c at its native locus and image cells during vegetative growth, nitrogen starvation, oxidative stress, and conditions that induce autophagy or organelle turnover.
  3. Loss-of-function phenotyping: construct deletion and zinc-coordinating-residue mutants, then measure growth, autophagic flux, organelle turnover, stress sensitivity, and chromatin-associated phenotypes.
  4. Biochemistry: test binding to modified histone peptides, phosphoinositides, candidate E2 enzymes, ubiquitin, and proteins identified by affinity purification–mass spectrometry.
  5. Catalytic tests: if RING-like E2 binding is observed, conduct in-vitro ubiquitination assays and identify physiological substrates. If lipid binding is observed, determine specificity and affinity quantitatively.

Final annotation recommendation

Recommended concise annotation: “SPCC126.07c/O94400 is a poorly characterized Schizosaccharomyces pombe protein containing predicted PHD/RING-like zinc-finger signatures. Its molecular function, biological pathway, substrates or partners, and subcellular localization have not been experimentally established.”

The label asr1 should be treated as provisional until confirmed against a current curated S. pombe gene record. The PHRF1/Atg35 domain-family hit should not be converted into an autophagy or micropexophagy annotation without demonstrated orthology or direct experimental evidence.

References

  1. (klionsky2011acomprehensiveglossary pages 11-12): Daniel J Klionsky, Eric H. Baehrecke, John H. Brumell, Charleen T. Chu, Patrice Codogno, Ana Maria Cuervo, Jayanta Debnath, Vojo Deretic, Zvulun Elazar, Eeva-Liisa Eskelinen, Steven Finkbeiner, Juan Fueyo-Margareto, David A. Gewirtz, Marja Jäättelä, Guido Kroemer, Beth Levine, Thomas J. Melia, Noboru Mizushima, David C. Rubinsztein, Anne Simonsen, Andrew Thorburn, Michael Thumm, and Sharon A. Tooze. A comprehensive glossary of autophagy-related molecules and processes (2nd edition). Autophagy, 7:1273-1294, Nov 2011. URL: https://doi.org/10.4161/auto.7.11.17661, doi:10.4161/auto.7.11.17661. This article has 348 citations and is from a domain leading peer-reviewed journal.

  2. (klionsky2011acomprehensiveglossary pages 12-14): Daniel J Klionsky, Eric H. Baehrecke, John H. Brumell, Charleen T. Chu, Patrice Codogno, Ana Maria Cuervo, Jayanta Debnath, Vojo Deretic, Zvulun Elazar, Eeva-Liisa Eskelinen, Steven Finkbeiner, Juan Fueyo-Margareto, David A. Gewirtz, Marja Jäättelä, Guido Kroemer, Beth Levine, Thomas J. Melia, Noboru Mizushima, David C. Rubinsztein, Anne Simonsen, Andrew Thorburn, Michael Thumm, and Sharon A. Tooze. A comprehensive glossary of autophagy-related molecules and processes (2nd edition). Autophagy, 7:1273-1294, Nov 2011. URL: https://doi.org/10.4161/auto.7.11.17661, doi:10.4161/auto.7.11.17661. This article has 348 citations and is from a domain leading peer-reviewed journal.

  3. (klionsky2011acomprehensiveglossary pages 17-18): Daniel J Klionsky, Eric H. Baehrecke, John H. Brumell, Charleen T. Chu, Patrice Codogno, Ana Maria Cuervo, Jayanta Debnath, Vojo Deretic, Zvulun Elazar, Eeva-Liisa Eskelinen, Steven Finkbeiner, Juan Fueyo-Margareto, David A. Gewirtz, Marja Jäättelä, Guido Kroemer, Beth Levine, Thomas J. Melia, Noboru Mizushima, David C. Rubinsztein, Anne Simonsen, Andrew Thorburn, Michael Thumm, and Sharon A. Tooze. A comprehensive glossary of autophagy-related molecules and processes (2nd edition). Autophagy, 7:1273-1294, Nov 2011. URL: https://doi.org/10.4161/auto.7.11.17661, doi:10.4161/auto.7.11.17661. This article has 348 citations and is from a domain leading peer-reviewed journal.

Artifacts

Citations

  1. klionsky2011acomprehensiveglossary pages 11-12
  2. klionsky2011acomprehensiveglossary pages 12-14
  3. klionsky2011acomprehensiveglossary pages 17-18
  4. O94400
  5. 10.4161/auto.7.11.17661
  6. https://www.uniprot.org/uniprotkb/O94400/entry
  7. https://doi.org/10.4161/auto.7.11.17661
  8. https://doi.org/10.4161/auto.7.11.17661,