TraitMech

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unconventional protein secretion

traitmech:000648 · CLASS · PROPOSED

A physiological phenotype in which a eukaryotic microbial cell delivers protein cargo to the plasma membrane or extracellular space by a route that bypasses part or all of the conventional endoplasmic-reticulum-Golgi-plasma-membrane secretory itinerary.

Trait evidence (4)

  • DOI:10.3389/fcell.2022.852028
    Our results show that neosynthesized PmaA and PalI are translocated to the PM via Golgi-bypass, similar to nutrient transporters.

    PMID:35465316, PMC9021693. Scientific Abstract and selected Introduction, Results and Methods directly read in Europe PMC XML. The paper includes membrane-cargo delivery within unconventional protein secretion. Aspergillus nidulans fluorescent cargo, conditional trafficking repression and localization assays support Golgi bypass after COPII-dependent ER exit, not soluble extracellular release or universal ER independence. The reporters and promoter replacements are engineered; no natural canonical exemplar is inferred. Actual panels, supplements and independent recipient-strain provenance were not inspected.

  • DOI:10.7554/eLife.16299
    Under these conditions Acb1, but not Cof1, was detected in the cell wall extract of starving cells

    PMID:27115345, PMC4868542. Contiguous full-text Results s2-1 span, directly read in Europe PMC XML, not an abstract quote. Mild extraction detects intact Acb1 outside the plasma membrane of starved Saccharomyces cerevisiae with Cof1 leakage and Bgl2 extraction controls. This is cell-wall/periplasmic recovery, not direct detection in culture medium. Harsh extraction, some mutants, heat and DMSO can invalidate the assay through leakage. The direct assay differs from earlier SDF-2 bioactivity assays and does not support a Vps4 requirement. Static CUPS images do not prove a temporal sequence. Actual panels and strain provenance remain uninspected.

  • DOI:10.1083/jcb.201407119
    Altogether our findings indicate that CUPS are not specialized autophagosomes as suggested previously.

    PMID:25512390, PMC4274258. Scientific Abstract abstract2, distinct from the precis, and Introduction directly read in Europe PMC XML. The authors revise the earlier autophagosome interpretation of yeast CUPS. This is compartment-identity boundary evidence, not proof that every unconventional route excludes all autophagy-related machinery. Actual panels, full Methods and strain provenance were not inspected.

  • DOI:10.1083/jcb.202312120
    Notably, while CUPS remain stable, the modified TGN undergoes remodeling during the later stages of unconventional secretion.

    PMID:40015244, PMC11867701. Scientific Abstract, not the teaser, and selected Results, Discussion and Methods directly read in Europe PMC XML. Yeast CUPS contact a modified trans-Golgi network; this argues against defining the phenotype by absence of all Golgi-derived membranes. Rcy1 and v-SNARE perturbations reduce cell-wall recovery of Acb1, SOD1 and Trx2 with Cof1 controls. Drs2-deleted cells could not be assayed because of lysis concerns. Cargo collection and final delivery through the proposed CUPS-TGN route remain a model. BY4741 derivatives include engineered reporters and mutants. Actual panels and supplements were not visually inspected.

Provenance

Identifier source
TraitMech local identifier
Definition source
DOI:10.3389/fcell.2022.852028

Parent traits (1)

kg-microbe context

No kg-microbe node embedding matched this record in the 2026-04-25 deepwalk.

Discussions and Knowledge Gaps (2)

Open questions attached to this trait. Seeded by just knowledge-gap-scan and curated; see the corpus-wide index.

Keep cargo destinations and route-specific meanings distinct.

CURATION TODO OPEN unconventional-secretion-scope-and-mapping · raised by codex · 2026-10-06

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

The broad usage in DOI:10.3389/fcell.2022.852028 includes plasma-membrane delivery after ER entry; DOI:10.7554/eLife.16299 describes an ER-bypassing soluble-cargo route. Preserve both, rather than treating leaderless secretion, Golgi bypass or secretory autophagy as exact synonyms. This concerns traffic performed by a eukaryotic microbe, not its animal or plant host. An absent predicted signal peptide, ATG dependence, CUPS formation or protein detected after lysis alone is insufficient. Membrane localization does not establish soluble release. The degradative autophagy record traitmech:000638 is not a broader parent; exocytosis traitmech:000637 specifies fusion-pore release rather than an unconventional itinerary. Overlap is not disjointness. Obsolete METPO secretion classes do not supply an active exact term. Keep METPO:1000059 as parent and leave ontology equivalences and finer route hierarchy for human review.

Resolve natural exemplars and mechanisms separately for each route.

KNOWLEDGE GAP OPEN unconventional-secretion-exemplars-and-mechanisms · raised by codex · 2026-10-06

Not yet attached to a section of this record — a curator sets attaches_to (e.g. causal_graphs#some_edge) so the gap shows beside the mechanism it concerns.

Retain qualified laboratory observations without labeling engineered fluorescent cargo or conditional trafficking mutants as natural canonical exemplars. Natural strain provenance, source figures and accession-level functional evidence need further review before adding examples or a protein-resolved graph. The three CUPS papers share investigators and are not independent-laboratory replications; the Aspergillus study supports a different route, not replication of CUPS. No universal starvation trigger, signal-peptide absence, COPII independence, autophagosome or conserved export apparatus is asserted. ATG-dependent export remains a possible narrower research target, not an allocated additional trait.

Curation history

  1. · MINTED_TRAITMECH_ID · codex

    Added unconventional protein secretion with four DOI-backed snippets and explicit soluble-export, membrane-delivery, route and assay limits. Ignored-and-hidden searches and pinned METPO review found no exact record. Reserved METPO:1060100 in v524. Deferred unverified mappings, natural exemplars and protein mechanisms; existing records remain unchanged.

  2. · CURATED_WITH_LITERATURE · codex

    Clarified the conventional itinerary through plasma-membrane delivery (#1760), preserving the definition source's inclusion of unconventional post-Golgi export. No new route, cargo, taxon or universal mechanism is inferred.