PDI1

UniProt ID: P17967
Organism: Saccharomyces cerevisiae
Review Status: DRAFT
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Gene Description

PDI1 encodes the essential protein disulfide isomerase of the ER lumen, a multifunctional oxidoreductase required for formation and isomerization of disulfide bonds in secretory and cell-surface proteins. Pdi1p catalyzes both the oxidation of free thiols and the reduction/rearrangement of non-native disulfide bonds, ensuring correct folding of ER client proteins. It forms a complex with the exomannosidase Mnl1p to recognize misfolded glycoproteins, process Man8GlcNAc2 oligosaccharides to Man7GlcNAc2, and reduce disulfide bonds of demannosylated substrates to generate unfolded polypeptides for retrotranslocation as part of ER-associated degradation (ERAD). Pdi1p also maintains Mnl1p solubility in the ER lumen and activates the oxidase Ero1p, which regenerates oxidized Pdi1p. Its closest human counterpart is PDIA1/P4HB, the canonical, general-substrate protein disulfide-isomerase of the mammalian ER.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0005783 endoplasmic reticulum
IBA
GO_REF:0000033
ACCEPT
Summary: Manual review: endoplasmic reticulum is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0006457 protein folding
IBA
GO_REF:0000033
ACCEPT
Summary: Protein folding (oxidative folding of secretory clients) is a core biological process for Pdi1p. Oxidizing equivalents flow Ero1p->Pdi1p->substrate, and a principal experimental client is carboxypeptidase Y (CPY), whose maturation requires Pdi1p disulfide formation and isomerization.
Reason: Retained as supported or plausible for this gene and evidence context.
Supporting Evidence:
file:yeast/PDI1/PDI1-deep-research-falcon.md
A widely supported model is that oxidizing equivalents flow from **Ero1p β†’ Pdi1p β†’ substrates**. Ero1p is essential for ER thiol oxidation
GO:0034976 response to endoplasmic reticulum stress
IBA
GO_REF:0000033
ACCEPT
Summary: Manual review: response to endoplasmic reticulum stress is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0003756 protein disulfide isomerase activity
IBA
GO_REF:0000033
ACCEPT
Summary: Protein disulfide isomerase activity is the core molecular function of Pdi1p, well supported by biochemical and genetic evidence in yeast. Pdi1p both introduces disulfides (oxidase) and rearranges incorrect disulfides (isomerase), with the active sites partially reduced (~32%) in vivo to support isomerization.
Reason: Retained as supported or plausible for this gene and evidence context.
Supporting Evidence:
file:yeast/PDI1/PDI1-deep-research-falcon.md
active-site cysteines are oxidized (forming a disulfide), it can oxidize client proteins; when reduced (dithiol), it can reduce or isomerize incorrect disulfides
GO:0003756 protein disulfide isomerase activity
IEA
GO_REF:0000120
ACCEPT
Summary: Manual review: protein disulfide isomerase activity is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0005788 endoplasmic reticulum lumen
IEA
GO_REF:0000044
ACCEPT
Summary: Manual review: endoplasmic reticulum lumen is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0006457 protein folding
IEA
GO_REF:0000117
ACCEPT
Summary: Manual review: protein folding is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0015035 protein-disulfide reductase activity
IEA
GO_REF:0000117
ACCEPT
Summary: Protein-disulfide reductase activity is supported by the reductive branch of Pdi1p chemistry: when its active sites are reduced, Pdi1p reduces/rearranges incorrect disulfides, and in the Htm1/Mnl1-Pdi1 ERAD complex Pdi1 can be switched toward acting as a disulfide reductase on misfolded glycoproteins.
Reason: Retained as supported or plausible for this gene and evidence context.
Supporting Evidence:
file:yeast/PDI1/PDI1-deep-research-falcon.md
the **Htm1/Mnl1–Pdi1** complex proposes that association with the mannosidase can **block canonical oxidative function** of Pdi1 and enable it to operate as a **disulfide reductase** for misfolded glycoproteins
GO:0016853 isomerase activity
IEA
GO_REF:0000043
ACCEPT
Summary: Manual review: isomerase activity is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0051082 unfolded protein binding
IEA
GO_REF:0000117
MARK AS OVER ANNOTATED
Summary: Manual review: unfolded protein binding is too generic or over-extended for PDI1.
Reason: Marked over-annotated because more specific terms capture the biology more accurately.
GO:0005515 protein binding
IPI
PMID:16368681
Domain architecture of protein-disulfide isomerase facilitat...
MARK AS OVER ANNOTATED
Summary: Manual review: protein binding is too generic or over-extended for PDI1.
Reason: Marked over-annotated because more specific terms capture the biology more accurately.
GO:0005515 protein binding
IPI
PMID:16429126
Proteome survey reveals modularity of the yeast cell machine...
MARK AS OVER ANNOTATED
Summary: Manual review: protein binding is too generic or over-extended for PDI1.
Reason: Marked over-annotated because more specific terms capture the biology more accurately.
GO:0005515 protein binding
IPI
PMID:16554755
Global landscape of protein complexes in the yeast Saccharom...
MARK AS OVER ANNOTATED
Summary: Manual review: protein binding is too generic or over-extended for PDI1.
Reason: Marked over-annotated because more specific terms capture the biology more accurately.
GO:0005515 protein binding
IPI
PMID:19124653
Htm1 protein generates the N-glycan signal for glycoprotein ...
MARK AS OVER ANNOTATED
Summary: Manual review: protein binding is too generic or over-extended for PDI1.
Reason: Marked over-annotated because more specific terms capture the biology more accurately.
GO:0005515 protein binding
IPI
PMID:27107014
An inter-species protein-protein interaction network across ...
MARK AS OVER ANNOTATED
Summary: Manual review: protein binding is too generic or over-extended for PDI1.
Reason: Marked over-annotated because more specific terms capture the biology more accurately.
GO:0005515 protein binding
IPI
PMID:37968396
The social and structural architecture of the yeast protein ...
MARK AS OVER ANNOTATED
Summary: Manual review: protein binding is too generic or over-extended for PDI1.
Reason: Marked over-annotated because more specific terms capture the biology more accurately.
GO:0005788 endoplasmic reticulum lumen
IDA
PMID:21700223
A complex of Pdi1p and the mannosidase Htm1p initiates clear...
ACCEPT
Summary: Endoplasmic reticulum lumen is the established site of Pdi1p function. Pdi1p is a soluble ER luminal resident with a C-terminal AIHDEL/HDEL retrieval motif that mediates ER-Golgi retrieval cycling, keeping it in the ER lumen.
Reason: Retained as supported or plausible for this gene and evidence context.
Supporting Evidence:
file:yeast/PDI1/PDI1-deep-research-falcon.md
Pdi1p is an **ER luminal resident** protein. A systematic yeast ER-resident analysis reports its C-terminal ER retrieval motif as **AIHDEL**
GO:1900103 positive regulation of endoplasmic reticulum unfolded protein response
IDA
PMID:21700223
A complex of Pdi1p and the mannosidase Htm1p initiates clear...
ACCEPT
Summary: Manual review: positive regulation of endoplasmic reticulum unfolded protein response is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0005783 endoplasmic reticulum
HDA
PMID:26928762
One library to make them all: streamlining the creation of y...
ACCEPT
Summary: Manual review: endoplasmic reticulum is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0036508 protein alpha-1,2-demannosylation
IDA
PMID:21700223
A complex of Pdi1p and the mannosidase Htm1p initiates clear...
ACCEPT
Summary: Manual review: protein alpha-1,2-demannosylation is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:1904382 mannose trimming involved in glycoprotein ERAD pathway
IDA
PMID:21700223
A complex of Pdi1p and the mannosidase Htm1p initiates clear...
ACCEPT
Summary: Pdi1p participates in glycoprotein ERAD as part of a complex with the mannosidase Htm1/Mnl1; within this complex Pdi1 can be switched from oxidative folding toward disulfide reduction of misfolded glycoproteins destined for retrotranslocation.
Reason: Retained as supported or plausible for this gene and evidence context.
Supporting Evidence:
file:yeast/PDI1/PDI1-deep-research-falcon.md
the **Htm1/Mnl1–Pdi1** complex proposes that association with the mannosidase can **block canonical oxidative function** of Pdi1 and enable it to operate as a **disulfide reductase** for misfolded glycoproteins
GO:1904382 mannose trimming involved in glycoprotein ERAD pathway
IMP
PMID:21700223
A complex of Pdi1p and the mannosidase Htm1p initiates clear...
ACCEPT
Summary: Manual review: mannose trimming involved in glycoprotein ERAD pathway is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:1904382 mannose trimming involved in glycoprotein ERAD pathway
IGI
PMID:21700223
A complex of Pdi1p and the mannosidase Htm1p initiates clear...
ACCEPT
Summary: Manual review: mannose trimming involved in glycoprotein ERAD pathway is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:1904382 mannose trimming involved in glycoprotein ERAD pathway
IDA
PMID:27053108
A Complex of Htm1 and the Oxidoreductase Pdi1 Accelerates De...
ACCEPT
Summary: Manual review: mannose trimming involved in glycoprotein ERAD pathway is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0005515 protein binding
IPI
PMID:16002399
Interactions among yeast protein-disulfide isomerase protein...
MARK AS OVER ANNOTATED
Summary: Manual review: protein binding is too generic or over-extended for PDI1.
Reason: Marked over-annotated because more specific terms capture the biology more accurately.
GO:0051082 unfolded protein binding
IDA
PMID:16002399
Interactions among yeast protein-disulfide isomerase protein...
MARK AS OVER ANNOTATED
Summary: Manual review: unfolded protein binding is too generic or over-extended for PDI1.
Reason: Marked over-annotated because more specific terms capture the biology more accurately.
GO:0003756 protein disulfide isomerase activity
IMP
PMID:11157982
Functional differences in yeast protein disulfide isomerases...
ACCEPT
Summary: Manual review: protein disulfide isomerase activity is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0003756 protein disulfide isomerase activity
IDA
PMID:16002399
Interactions among yeast protein-disulfide isomerase protein...
ACCEPT
Summary: Manual review: protein disulfide isomerase activity is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0003756 protein disulfide isomerase activity
IDA
PMID:16413482
The crystal structure of yeast protein disulfide isomerase s...
ACCEPT
Summary: Manual review: protein disulfide isomerase activity is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0005788 endoplasmic reticulum lumen
IDA
PMID:1761554
The Saccharomyces cerevisiae TRG1 gene is essential for grow...
ACCEPT
Summary: Manual review: endoplasmic reticulum lumen is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0006457 protein folding
IMP
PMID:11157982
Functional differences in yeast protein disulfide isomerases...
ACCEPT
Summary: Manual review: protein folding is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.
GO:0015035 protein-disulfide reductase activity
IDA
PMID:16002399
Interactions among yeast protein-disulfide isomerase protein...
ACCEPT
Summary: Manual review: protein-disulfide reductase activity is consistent with known biology of PDI1.
Reason: Retained as supported or plausible for this gene and evidence context.

References

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Deep Research

Falcon

(PDI1-deep-research-falcon.md)

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πŸ“š Additional Documentation

Notes

(PDI1-notes.md)

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Bioreason Rl Predictions

(PDI1-bioreason-rl-predictions.md)

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Bioreason Rl Review

(PDI1-bioreason-rl-review.md)

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πŸ“„ View Raw YAML

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