Research, Research Reports

Reduced TORC1 signaling abolishes mitochondrial dysfunctions and shortened chronological lifespan of Isc1p-deficient cells

Vitor Teixeira1,2, Tânia C. Medeiros1, Rita Vilaça1,2, Pedro Moradas-Ferreira1,2, and Vítor Costa1,2

Overall, this article shows that the TORC1-Sch9p axis is deregulated in Isc1p-deficient Saccharomyces cerevisiae cells, contributing to mitochondrial dysfunction, enhanced oxidative stress sensitivity and premature aging of isc1Δ cells.

Early manifestations of replicative aging in the yeast Saccharomyces cerevisiae.

Maksim I. Sorokin1,3, Dmitry A. Knorre2,3, and Fedor F. Severin2,3

The data preseted herein suggest that retrograde signaling starts to malfunction in relatively young cells, leading to accumulation of heterogeneous mitochondria within one cell. The latter may further contribute to a decline in stress resistances.

Tracking autophagy during proliferation and differentiation of Trypanosoma brucei

William R. Proto1, Nathaniel G. Jones1, Graham H. Coombs2, and Jeremy C. Mottram1

This article provides insights into the function of autophagy, a cellular degradation and recycling pathway, in the protozoan parasite Trypanosoma brucei.

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Increased spontaneous recombination in RNase H2-deficient cells arises from multiple contiguous rNMPs and not from single rNMP residues incorporated by DNA polymerase epsilon

May 15, 2016

Ribonucleotides (rNMPs) can become embedded in DNA from insertion by DNA polymerases, failure to remove Okazaki fragment primers, R-loops that can prime replication, and RNA/cDNA-mediated recombination. We report here that recombination is not stimulated by rNMPs incorporated by the replicative polymerase epsilon. Instead, recombination seems to be stimulated by multiple contiguous rNMPs, which may arise from R-loops or replication priming events.

Filamentation protects Candida albicans from amphotericin B-induced programmed cell death via a mechanism involving the yeast metacaspase, MCA1

April 25, 2016

Candida albicans proliferates in two distinct cell types: blastopores and filaments. Programmed cell death is a controlled form of cell suicide that occurs when C. albicans cells are exposed to fungicidal drugs like amphotericin B and caspofungin, and to other stressful conditions. We provide evidence that programmed cell death is cell-type specific in yeast: Filamentous C. albicans cells are more resistant to amphotericin B- and caspofungin-induced programmed cell death than their blastospore counterparts. Our genetic data suggest that this phenomenon is mediated by a protective mechanism involving the yeast metacaspase, MCA1.

Towards understanding the gliotoxin detoxification mechanism: in vivo thiomethylation protects yeast from gliotoxin cytotoxicity

February 19, 2016

Gliotoxin is a mycotoxin produced by some species of ascomycete fungi including the opportunistic human pathogen Aspergillus fumigatus. In order to produce gliotoxin the host organism needs to have evolved a self-protection mechanism. The authors demonstrate that the activity of a novel thiomethyltransferase is requiered for protection against exogenous gliotoxin and provide implications for understanding the evolution of gliotoxin self-protection mechanisms.

The transcriptional repressor Sum1p counteracts Sir2p in regulation of the actin cytoskeleton, mitochondrial quality control and replicative lifespan in Saccharomyces cerevisiae

January 18, 2016

Increasing the stability or dynamics of the actin cytoskeleton can extend lifespan in C. elegans and S. cerevisiae. Actin cables of budding yeast, bundles of actin filaments that mediate cargo transport, affect lifespan control through effects on mitochondrial quality control. Here, we report that Sum1p and Sir2p inversely regulate actin and mitochondrial maintenance, as well as lifespan.

Micafungin induced apoptosis in Candida parapsilosis independent of its susceptibility to micafungin

October 23, 2015

Shirazi et al. studied the effects of the cell wall inhibitor micafungin (MICA) on apoptosis in both MICA-susceptible (MICA-S) and MICA–non-susceptible (MICA-NS) Candida parapsilosis.

Human Thyroid Cancer-1 (TC-1) is a vertebrate specific oncogenic protein that protects against copper and pro-apoptotic genes in yeast

June 25, 2015

The human Thyroid Cancer-1 (hTC-1) protein, also known as C8orf4 was initially identified as a gene that was up-regulated in human thyroid cancer. This article reports that hTC-1 is a peptide that prevents the effects of over-expressing Bax in yeast. In sum, the results indicate that hTC-1 is a pro-survival protein that retains its function when heterologously expressed in yeast. Thus yeast is a useful model to characterize the potential roles in cell death and survival of cancer related genes.

Exogenous folates stimulate growth and budding of Candida glabrata

May 1, 2015

Folate, vitamin B9, is well recognized as being essential for cell growth. The utilization of folate is common to all cells, but the source of it may be quite different. This article reports a novel response of yeast to folates that may increase the utility of yeast as a model to study folate transport and signaling.

Loss of wobble uridine modification in tRNA anticodons interferes with TOR pathway signaling

November 29, 2014

The herein presented data suggest that proper TOR signaling requires intact tRNA modifications and that loss of U34 modifications impinges on the TOR-sensitive NCR branch via Gln3 misregulation.

Exogenous addition of histidine reduces copper availability in the yeast Saccharomyces cerevisiae

July 6, 2014

The herein presented results indicate that in Saccharomyces cerevisiae, histidine cytotoxicity is associated with low copper availability inside cells, not with impaired copper uptake. Furthermore, it suggests that histidine cytotoxicity is involved in deficiency of mitochondrial copper.

Deletion of AIF1 but not of YCA1/MCA1 protects Saccharomyces cerevisiae and Candida albicans cells from caspofungin-induced programmed cell death

January 15, 2014

This work suggests that deleting AIF1 but not YCA1/MCA1 protects S. cerevisiae and Candida albicans from caspofungin-induced cell death. This is not only the first time that AIF1 has been specifically tied to cell death in Candida but also the first time that caspofungin resistance has been linked to the cell death machinery in yeast.