The histone H2B Arg95 residue links the pheromone response pathway to rapamycin-induced G1 arrest in yeast

Sulaiman, Abdallah Alhaj; Ali, Reem; Aouida, Mustapha; Moovarkumudalvan, Balasubramanian; Ramotar, Dindial

doi:10.1038/s41598-022-14053-9

Cited by 3 publications

(3 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rapamycin is an immunosuppressant used in organ transplants and for treating various cancers. It acts by inhibiting the TOR kinase pathway and mimicking starvation conditions leading to cell cycle arrest in the G1 phase [ 29 , 30 , 31 ]. We performed spot test and growth curve analyses with rapamycin under similar conditions as for CHX, and found that the agp2Δ mutant showed normal WT resistance to rapamycin, excluding the possibility that Agp2 is involved in the recognition of a broad array of drugs ( Figure S3 ).…”

Section: Resultsmentioning

confidence: 99%

The Yeast Permease Agp2 Senses Cycloheximide and Undergoes Degradation That Requires the Small Protein Brp1-Cellular Fate of Agp2 in Response to Cycloheximide

Mohanty

Sulaiman

Moovarkumudalvan

et al. 2023

IJMS

Self Cite

View full text Add to dashboard Cite

The Saccharomyces cerevisiae Agp2 is a plasma membrane protein initially reported to be an uptake transporter for L-carnitine. Agp2 was later rediscovered, together with three additional proteins, Sky1, Ptk2, and Brp1, to be involved in the uptake of the polyamine analogue bleomycin-A5, an anticancer drug. Mutants lacking either Agp2, Sky1, Ptk2, or Brp1 are extremely resistant to polyamines and bleomycin-A5, suggesting that these four proteins act in the same transport pathway. We previously demonstrated that pretreating cells with the protein synthesis inhibitor cycloheximide (CHX) blocked the uptake of fluorescently labelled bleomycin (F-BLM), raising the possibility that CHX could either compete for F-BLM uptake or alter the transport function of Agp2. Herein, we showed that the agp2Δ mutant displayed striking resistance to CHX as compared to the parent, suggesting that Agp2 is required to mediate the physiological effect of CHX. We examined the fate of Agp2 as a GFP tag protein in response to CHX and observed that the drug triggered the disappearance of Agp2 in a concentration- and time-dependent manner. Immunoprecipitation analysis revealed that Agp2-GFP exists in higher molecular weight forms that were ubiquitinylated, which rapidly disappeared within 10 min of treatment with CHX. CHX did not trigger any significant loss of Agp2-GFP in the absence of the Brp1 protein; however, the role of Brp1 in this process remains elusive. We propose that Agp2 is degraded upon sensing CHX to downregulate further uptake of the drug and discuss the potential function of Brp1 in the degradation process.

show abstract

Section: Resultsmentioning

confidence: 99%

The Yeast Permease Agp2 Senses Cycloheximide and Undergoes Degradation That Requires the Small Protein Brp1-Cellular Fate of Agp2 in Response to Cycloheximide

Mohanty

Sulaiman

Moovarkumudalvan

et al. 2023

IJMS

Self Cite

View full text Add to dashboard Cite

show abstract

“…Drugs were added to the cells at the indicated concentrations and growth was monitored for 24 h in a TECAN plate reader with shaking. The temperature was set to 30 °C and the OD was taken every 2 h. The result was plotted as a graph of OD 600 against the time (Sulaiman et al, 2022). For HU sensitivity, the spot test was performed as above.…”

Section: Qxn and Hu Sensitivities Of The Single And Double Mutantmentioning

confidence: 99%

“…One approach to understanding the mechanism of action of QXN is to take advantage of the available tools in the budding yeast Saccharomyces cerevisiae (Sulaiman et al, 2022;Mohanty et al, 2023;Sulaiman et al, 2023). These include a collection of ~4,800 haploid mutants, each deleted for a single non-essential gene.…”

Section: Introductionmentioning

confidence: 99%

Mft1, identified from a genome-wide screen of the yeast haploid mutants, mediates cell cycle arrest to counteract quinoxaline-induced toxicity

Sulaiman,

Al-Ansari,

Ali

et al. 2024

Front. Genet.

Self Cite

View full text Add to dashboard Cite

Quinoxaline is a heterocyclic compound with a two-membered ring structure that undergoes redox cycling to produce toxic free radicals. It has antiviral, antibacterial, antifungal, and antitumor activities. However, the biological functions that are involved in mounting a response against the toxic effects of quinoxaline have not been investigated. Herein, we performed a genome-wide screen using the yeast haploid mutant collection and reported the identification of 12 mutants that displayed varying sensitivity towards quinoxaline. No mutant was recovered that showed resistance to quinoxaline. The quinoxaline-sensitive mutants were deleted for genes that encode cell cycle function, as well as genes that belong to other physiological pathways such as the vacuolar detoxification process. Three of the highly sensitive gene-deletion mutants lack the DDC1, DUN1, and MFT1 genes. While Ddc1 and Dun1 are known to perform roles in the cell cycle arrest pathway, the role of Mft1 remains unclear. We show that the mft1Δ mutant is as sensitive to quinoxaline as the ddc1Δ mutant. However, the double mutant ddc1Δ mft1Δ lacking the DDC1 and MFT1 genes, is extremely sensitive to quinoxaline, as compared to the ddc1Δ and mft1Δ single mutants. We further show that the mft1Δ mutant is unable to arrest in the G2/M phase in response to the drug. We conclude that Mft1 performs a unique function independent of Ddc1 in the cell cycle arrest pathway in response to quinoxaline exposure. This is the first demonstration that quinoxaline exerts its toxic effect likely by inducing oxidative DNA damage causing cell cycle arrest. We suggest that clinical applications of quinoxaline and its derivatives should entail targeting cancer cells with defective cell cycle arrest.

show abstract

The histone H2B Arg95 residue efficiently recruits the transcription factor Spt16 to mediate Ste5 expression of the pheromone response pathway

Sulaiman

Ali

Ramotar

2023

Sci Rep

View full text Add to dashboard Cite

In yeast Saccharomyces cerevisiae, the immunosuppressant rapamycin inhibits the TORC1 kinase causing rapid alteration in gene expression and leading to G1 arrest. We recently reported the isolation and characterization from the histone mutant collection of a histone H2B R95A mutant that displays resistance to rapamycin. This mutant is defective in the expression of several genes belonging to the pheromone response pathway including STE5 encoding a scaffold protein that promotes the activation of downstream MAP kinases. Cells lacking Ste5 cannot arrest the cell cycle in response to rapamycin and as a consequence exhibit similar resistance to rapamycin as the H2B R95A mutant. Herein, we show that the H2B R95A mutation weakens the association of H2B with Spt16 a component of the FACT complex (FAcilitates Chromatin Transcription), and an essential factor that interacts with the histone H2A-H2B dimer to promote transcription and preserve chromatin integrity. From a collection of spt16 mutants, spt16 E857K and spt16-11 showed striking sensitivity to rapamycin as compared to the parent strain. spt16 E857K and spt16-11 expressed distinct forms of Ste5, while a suppressor mutation H2B A84D of the spt16-11 mutant prevents the expression of Ste5 and confers marked resistance to rapamycin. We interpret these findings to suggest that the Arg95 residue of histone H2B is required to recruit Spt16 to maintain the expression of STE5, which performs a role to arrest cells in the G1 phase in response to rapamycin.

show abstract

The histone H2B Arg95 residue links the pheromone response pathway to rapamycin-induced G1 arrest in yeast

Cited by 3 publications

References 51 publications

The Yeast Permease Agp2 Senses Cycloheximide and Undergoes Degradation That Requires the Small Protein Brp1-Cellular Fate of Agp2 in Response to Cycloheximide

The Yeast Permease Agp2 Senses Cycloheximide and Undergoes Degradation That Requires the Small Protein Brp1-Cellular Fate of Agp2 in Response to Cycloheximide

Mft1, identified from a genome-wide screen of the yeast haploid mutants, mediates cell cycle arrest to counteract quinoxaline-induced toxicity

The histone H2B Arg95 residue efficiently recruits the transcription factor Spt16 to mediate Ste5 expression of the pheromone response pathway

Contact Info

Product

Resources

About