Annotation inferences using phylogenetic trees

Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt

GO_REF:0000120

Combined Automated Annotation using Multiple IEA Methods

PMID:16449570

Target hub proteins serve as master regulators of development in yeast.

PMID:19111667

A library of yeast transcription factor motifs reveals a widespread function for Rsc3 in targeting nucleosome exclusion at promoters.

PMID:19158363

High-resolution DNA-binding specificity analysis of yeast transcription factors.

PMID:8114741

Induction of pseudohyphal growth by overexpression of PHD1, a Saccharomyces cerevisiae gene related to transcriptional regulators of fungal development.

file:yeast/PHD1/PHD1-deep-research-perplexity.md

Deep research report on PHD1

file:yeast/PHD1/PHD1-deep-research-falcon.md

Falcon (Edison) deep research report on PHD1

Phd1 is intrinsically unstable; its degradation is initiated by Cdk8-dependent phosphorylation (Cdk8 is associated with the RNA polymerase II Mediator complex), with a short half-life (~10-15 min) in rich medium that increases to >45 min in cdk8-disrupted cells.

"Raithatha et al. (2012) provide experimental evidence that **Phd1 is intrinsically unstable** and that its degradation is initiated via **Cdk8-dependent phosphorylation** (Cdk8 is a kinase associated with the RNA polymerase II Mediator complex). "
Under nitrogen limitation, Cdk8 activity falls and Phd1 becomes progressively stabilized (half-life ~40 min after 2 h and >45 min after 4 h in SLAD medium), coupling nutrient sensing to accumulation of the differentiation regulator.

"Under **nitrogen limitation**, Phd1 becomes progressively stabilized: half-life increases to **~40 min after 2 h** in nitrogen-limiting SLAD and to **>45 min after 4 h**, consistent with a differentiation-triggered stabilization mechanism. "
A natural S92F polymorphism in the filamentous Sigma1278b background eliminates a Cdk8 phosphosite, stabilizing Phd1 and enhancing filamentation, providing a causal link between phosphorylation site, protein stability, and phenotype.

"a **natural polymorphism** in a differentiating strain background (1278b) that removes a candidate Cdk8 phosphosite (S92F), stabilizing Phd1 and enhancing filamentation, supporting causality between **phosphorylation site, stability, and phenotype**. "
Phd1 and Ash1 positively regulate expression of the cell-surface flocculin Flo11 and are largely required for filamentation in a sok2/sok2 hyperfilamentous background, placing Phd1 in a Sok2->Phd1/Ash1/Swi5 transcription-factor cascade converging on FLO11.

"Pan & Heitman (2000) report that **Phd1 and Ash1 regulate expression of the cell surface protein Flo11**, and that both factors are **largely required** for filamentation in a **sok2** hyperfilamentous background. "
Synthetic gene-regulation circuits controlling native PHD1 and FLO8 expression are sufficient to trigger pseudohyphal growth in both diploid and haploid strains, even in rich media, establishing PHD1 as an inducible driver of differentiation.

"Pothoulakis & Ellis (2018) engineered synthetic regulatory systems to control expression of **native PHD1 and FLO8**, demonstrating that externally controlled induction of these transcription factors can **trigger pseudohyphal growth** in both diploid and haploid strains, including in rich media. "
In a structured-colony strain (F13), PHD1/YKL043W clusters with genes whose expression correlates with colony structure, yet phd1-delta alone had little effect on colony morphology at day 5 (unlike flo11-delta or msb2-delta), indicating PHD1 is redundant/nonessential for loss-of-function in some backgrounds despite a strong gain-of-function phenotype.

"whereas **phd1Δ** retained central smooth plus outer structured zones at day 5, unlike **flo11Δ** or **msb2Δ** (cromie2024spatiotemporalpatternsof pages 21-23) "

PMID:22124158

Cdk8 regulates stability of the transcription factor Phd1 to control pseudohyphal differentiation of Saccharomyces cerevisiae.

Phd1 is an unstable protein whose degradation is initiated through Cdk8-dependent phosphorylation of the RNA polymerase II Mediator subcomplex; Phd1 is stabilized by cdk8 disruption, and a Sigma1278b sequence polymorphism that eliminates a Cdk8 phosphorylation site both stabilizes Phd1 and enhances differentiation.

"Phd1 is an unstable protein whose degradation is initiated through phosphorylation by Cdk8 of the RNA polymerase II mediator subcomplex. Phd1 is stabilized by cdk8 disruption, and the naturally filamenting Σ1278b strain was found to have a sequence polymorphism that eliminates a Cdk8 phosphorylation site, which both stabilizes the protein and contributes to enhanced differentiation. "
In nitrogen-starved cells PHD1 expression is upregulated and the Phd1 protein becomes stabilized, causing its accumulation during differentiation; Cdk8 activity is inhibited under limiting nutrients, driving differentiation through stabilization of multiple transcription factors including Phd1.

"In nitrogen-starved cells, PHD1 expression is upregulated and the Phd1 protein becomes stabilized, which causes its accumulation during differentiation. "
Phd1 regulates expression of most other transcription factors involved in differentiation and can induce filamentation on its own when overproduced.

"Phd1 is important for this process in that it regulates expression of most other transcription factors involved in differentiation and can induce filamentation on its own when overproduced. "

PMID:11046133

Sok2 regulates yeast pseudohyphal differentiation via a transcription factor cascade that regulates cell-cell adhesion.

Genes encoding Phd1, Ash1, and Swi5 are induced in sok2/sok2 hyperfilamentous mutants; Phd1 and Ash1 regulate expression of the cell-surface protein Flo11 (required for filamentous growth) and are largely required for filamentation, defining a transcription-factor cascade controlling cell-cell adhesion.

"Phd1 and Ash1 regulated expression of the cell surface protein Flo11, which is required for filamentous growth, and were largely required for filamentation of sok2/sok2 mutant strains. These findings reveal that a complex transcription factor cascade regulates filamentation. "

PMID:34280314

The Complex Genetic Basis and Multilayered Regulatory Control of Yeast Pseudohyphal Growth.

Phd1 sits in a Sok2 -> Phd1/Ash1/Swi5 transcription-factor cascade that can regulate FLO11 independently of the PKA and MAPK pathways.

PMID:30271894

Synthetic gene regulation for independent external induction of the Saccharomyces cerevisiae pseudohyphal growth phenotype.

Controlling expression of the natural PHD1 and FLO8 genes via synthetic regulation is sufficient to trigger pseudohyphal growth in both diploid and haploid yeast, even in rich media, demonstrating PHD1 as an inducible driver of multicellular morphology.

"By controlling the expression of the natural PHD1 and FLO8 genes we are able to trigger pseudohyphal growth in both diploid and haploid yeast, even in different types of rich media. "

PMID:39637084

Spatiotemporal patterns of gene expression during development of a complex colony morphology.

In structured-colony strain F13, deletion of PHD1 (with SIM1, SRL1 and SVS1) had little effect on colony morphology at day 5, unlike deletion of FLO11 or MSB2 which abolished the structured phenotype, indicating PHD1 is dispensable/redundant for loss-of-function in this genetic background despite its strong gain-of-function phenotype.

"Deletion of other I9 genes tested (PHD1, SIM1, SRL1 and SVS1) had little effect on F13 colony morphology, retaining a central smooth and outer structured zone at day-5. "