Altered sterol metabolism in budding yeast affects mitochondrial iron-sulfur (Fe-S) cluster synthesis.

Ergosterol synthesis is essential for cellular growth and viability of the budding yeast , and intracellular sterol distribution and homeostasis are therefore highly regulated in this species. Erg25 is an iron-containing C4-methyl sterol oxidase that contributes to the conversion of 4,4-dimethylzymosterol to zymosterol, a precursor of ergosterol. The gene encodes an endoplasmic reticulum (ER)-associated protein, and here we identified a role for Erg29 in the methyl sterol oxidase step of ergosterol synthesis.

Prognostic value of pre-operative glucose-corrected maximum standardized uptake value in patients with non-small cell lung cancer after complete surgical resection and 5-year follow-up.

Introduction: In this study we evaluated the value of pre-operative glucose corrected maximum standard uptake value (GC-SUVmax) as prognostic factor in patients with early stage non-small cell lung cancer (NSCLC) after complete surgical resection.

Methods: This study was designed as a retrospectively evaluated single center study with prospective data registry. Inclusion criteria were: histologically proven stage I NSCLC, 18F-FDG-PET/CT scan prior to surgery, complete resection (R0) and follow up in our outpatient department.

The mannoprotein TIR3 (CAGL0C03872g) is required for sterol uptake in Candida glabrata.

Sterol uptake in the pathogenic fungus, Candida glabrata, occurs via the sterol transporter, CgAus1p. Azole inhibition of sterol biosynthesis can under certain circumstances be reversed by adding exogenously sterol. Here we demonstrate that the CgTIR3 (CAGL0C03872g) gene product is also required for sterol uptake, since Cgtir3Δ strains fail to take up sterol both aerobically and under hypoxic conditions.

Genome-wide survey of transcriptional initiation in the pathogenic fungus, Candida glabrata.

DNA sequencing of the 5'-flanking region of the transcriptome effectively identifies transcription initiation sites and also aids in identifying unknown genes. This study describes a comprehensive polling of transcription start sites and an analysis of full-length complementary DNAs derived from the genome of the pathogenic fungus Candida glabrata. A comparison of the sequence reads derived from a cDNA library prepared from cells grown under different culture conditions against the reference genomic sequence of the Candida Genome Database (CGD: http://www.

The COP9 signalosome is involved in the regulation of lipid metabolism and of transition metals uptake in Saccharomyces cerevisiae.

The COP9 signalosome (CSN) is a highly conserved eukaryotic protein complex which regulates the cullin RING family of ubiquitin ligases and carries out a deneddylase activity that resides in subunit 5 (CSN5). Whereas CSN activity is essential for the development of higher eukaryotes, several unicellular fungi including the budding yeast Saccharomyces cerevisiae can survive without a functional CSN. Nevertheless, the budding yeast CSN is biochemically active and deletion mutants of each of its subunits exhibit deficiency in cullins deneddylation, although the biological context of this activity is still unknown in this organism.

Characterization of a mutation that results in independence of oxidosqualene cyclase (Erg7) activity from the downstream 3-ketoreductase (Erg27) in the yeast ergosterol biosynthetic pathway.

In yeast, deletion of ERG27, which encodes the sterol biosynthetic enzyme, 3-keto-reductase, results in a concomitant loss of the upstream enzyme, Erg7p, an oxidosqualene cyclase (OSC). However, this phenomenon occurs only in fungi, as mammalian Erg27p orthologues are unable to rescue yeast Erg7p activity. In this study, an erg27 mutant containing the mouse ERG27 orthologue was isolated that was capable of growing without sterol supplementation (FGerg27).

Osh6 overexpression extends the lifespan of yeast by increasing vacuole fusion.

In yeast cells, the vacuole divides and fuses in each round of cell cycle. While mutants defective in vacuole fusion are "wild type" for vegetative growth, most have shortened replicative lifespans under caloric restriction (CR) condition, a manipulation that extends lifespan in wild type cells. To explore whether vacuole fusion extends lifespan, we screened for genes that can complement the fusion defect of selected mutants (erg6Δ, a sterol mutant; nyv1Δ,  a mutant involved in the vacuolar SNARE complex and vac8Δ, a vacuolar membrane protein mutant).

Identification of new surfaces of cofilin that link mitochondrial function to the control of multi-drug resistance.

ADF/cofilin family proteins are essential regulators of actin cytoskeletal dynamics. Recent evidence also implicates cofilin in the regulation of mitochondrial function. Here, we identify new functional surfaces of cofilin that are linked with mitochondrial function and stress responses in the budding yeast Saccharomyces cerevisiae.

Germline polymorphisms in patients with advanced nonsmall cell lung cancer receiving first-line platinum-gemcitabine chemotherapy: a prospective clinical study.

Background: The authors assessed the impact of germline polymorphisms on clinical outcome in patients with advanced nonsmall cell lung cancer (NSCLC) who received platinum-gemcitabine (PG) chemotherapy.

Methods: In total, 137 patients with stage IIIB/IV NSCLC were included who received first-line PG chemotherapy (74% of patients received cisplatin, and 26% received carboplatin). Twenty-three germline polymorphisms that were identified in peripheral blood samples were analyzed for progression-free survival (PFS), treatment response, overall survival (OS), and toxicity.

An "exacerbate-reverse" strategy in yeast identifies histone deacetylase inhibition as a correction for cholesterol and sphingolipid transport defects in human Niemann-Pick type C disease.

Niemann-Pick type C (NP-C) disease is a fatal lysosomal lipid storage disorder for which no effective therapy exists. A genome-wide, conditional synthetic lethality screen was performed using the yeast model of NP-C disease during anaerobiosis, an auxotrophic condition that requires yeast to utilize exogenous sterol. We identified 12 pathways and 13 genes as modifiers of the absence of the yeast NPC1 ortholog (NCR1) and quantified the impact of loss of these genes on sterol metabolism in ncr1Δ strains grown under viable aerobic conditions.

Growth defects resulting from inhibiting ERG20 and RAM2 in Candida glabrata.

Farnesyl pyrophosphate (FPP) is utilized for many cellular processes, including the production of dolichols, ubiquinone (CoQ), sterols, farnesylated heme A and prenylated proteins. This lipid synthesized by FPP synthetase (ERG20) becomes attached to target proteins by the prenyltransferases, CDC43/RAM2 and RAM1/RAM2 complexes after the formation of the C15 and C20 units, respectively. Defects in protein prenylation as a result of inhibiting these enzyme complexes lead to pleiotropic effects in all eukaryotes.

Divergent interactions involving the oxidosqualene cyclase and the steroid-3-ketoreductase in the sterol biosynthetic pathway of mammals and yeasts.

In mammals and yeasts, oxidosqualene cyclase (OSC) catalyzes the formation of lanosterol, the first cyclic intermediate in sterol biosynthesis. We used a murine myeloma cell line (NS0), deficient in the 17β-hydroxysteroid dehydrogenase type 7 (HSD17B7), as a model to study the potential interaction of the HSD17B7 with the OSC in mammals. HSD17B7 is the orthologue of the yeast steroid-3-ketoreductase (ERG27), an enzyme of ergosterol biosynthesis that plays a protective role towards OSC.

Metabolic response to iron deficiency in Saccharomyces cerevisiae.

Iron is an essential cofactor for enzymes involved in numerous cellular processes, yet little is known about the impact of iron deficiency on cellular metabolism or iron proteins. Previous studies have focused on changes in transcript and proteins levels in iron-deficient cells, yet these changes may not reflect changes in transport activity or flux through a metabolic pathway. We analyzed the metabolomes and transcriptomes of yeast grown in iron-rich and iron-poor media to determine which biosynthetic processes are altered when iron availability falls.

A sterol-regulatory element binding protein is required for cell polarity, hypoxia adaptation, azole drug resistance, and virulence in Aspergillus fumigatus.

At the site of microbial infections, the significant influx of immune effector cells and the necrosis of tissue by the invading pathogen generate hypoxic microenvironments in which both the pathogen and host cells must survive. Currently, whether hypoxia adaptation is an important virulence attribute of opportunistic pathogenic molds is unknown. Here we report the characterization of a sterol-regulatory element binding protein, SrbA, in the opportunistic pathogenic mold, Aspergillus fumigatus.

The Candida glabrata putative sterol transporter gene CgAUS1 protects cells against azoles in the presence of serum.

Objectives: The uptake of endogenous sterol from serum may allow Candida glabrata to survive azole treatment. This study aims to determine the contribution of a sterol transporter that alters fluconazole sensitivity in the presence of serum.

Methods: Bioinformatic analysis predicted CgAUS1 as the C.

Synthetically lethal interactions involving loss of the yeast ERG24: the sterol C-14 reductase gene.

ERG2 and ERG24 are yeast sterol biosynthetic genes which are targets of morpholine antifungal compounds. ERG2 and ERG24 encode the C-8 sterol isomerase and the C-14 reductase, respectively. ERG2 is regarded as a non-essential gene but the viability of ERG24 depends on genetic background, type of medium, and CaCl(2) concentration.

Dap1/PGRMC1 binds and regulates cytochrome P450 enzymes.

Cytochrome P450 enzymes are heme-dependent monoxygenases that play a central role in human physiology. Despite the numerous physiological processes that P450 enzymes impact, the electron donors P450 oxidoreductase and cytochrome b5 are the only proteins known to interact with and modulate the activity of ER microsomal P450s. Here, we report that Dap1/PGRMC1 is required for ER P450 function in yeast and humans.

Molecular and enzymatic characterizations of novel bifunctional 3beta-hydroxysteroid dehydrogenases/C-4 decarboxylases from Arabidopsis thaliana.

We have isolated two cDNAs from Arabidopsis thaliana encoding bifunctional 3beta-hydroxysteroid dehydrogenase/C-4 decarboxylases (3betaHSD/D) involved in sterol synthesis, termed At3betaHSD/D1 and At3betaHSD/D2. Transformation of the yeast ergosterol auxotroph erg26 mutant, which lacks 3betaHSD/D activity, with the At3betaHSD/D1 isoform or with At3betaHSD/D2 isoform containing a C-terminal At3betaHSD/D1 endoplasmic reticulum-retrieval sequence restored growth and ergosterol synthesis in erg26. An in vitro enzymatic assay revealed high 3betaHSD/D activity for both isoenzymes in the corresponding microsomal extracts.

Cumulative mutations affecting sterol biosynthesis in the yeast Saccharomyces cerevisiae result in synthetic lethality that is suppressed by alterations in sphingolipid profiles.

UPC2 and ECM22 belong to a Zn(2)-Cys(6) family of fungal transcription factors and have been implicated in the regulation of sterol synthesis in Saccharomyces cerevisiae and Candida albicans. Previous reports suggest that double deletion of these genes in S. cerevisiae is lethal depending on the genetic background of the strain.

Optical spectroscopy for the classification of malignant lesions of the bronchial tree.

Optical spectroscopy may be used for in vivo, noninvasive distinction of malignant from normal tissue. The aim of our study was to analyze the accuracy of various optical spectroscopic techniques for the classification of cancerous lesions of the bronchial tree. We developed a fiberoptic instrument allowing the measurement of autofluorescence spectroscopy (AFS), diffuse reflectance spectroscopy (DRS), and differential path length spectroscopy (DPS) during bronchoscopy.

Endoplasmic reticulum-associated degradation is required for cold adaptation and regulation of sterol biosynthesis in the yeast Saccharomyces cerevisiae.

Endoplasmic reticulum-associated degradation (ERAD) mediates the turnover of short-lived and misfolded proteins in the ER membrane or lumen. In spite of its important role, only subtle growth phenotypes have been associated with defects in ERAD. We have discovered that the ERAD proteins Ubc7 (Qri8), Cue1, and Doa10 (Ssm4) are required for growth of yeast that express high levels of the sterol biosynthetic enzyme, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR).

A systematic study of yeast sterol biosynthetic protein-protein interactions using the split-ubiquitin system.

Sterol biosynthesis occurs in the ER and most sterol biosynthetic enzymes have transmembrane domains. However, due to difficulties in characterizing membrane protein-protein interactions, the nature of the sterol biosynthetic complex as well as in vivo interactions between various enzymes have not been described. We employed a split-ubiquitin membrane protein yeast two-hybrid system to characterize interactions between sterol biosynthetic proteins.

Erg28p is a key protein in the yeast sterol biosynthetic enzyme complex.

Previously, a microarray expression study in the yeast Saccharomyces cerevisiae indicated that the ERG28 gene was strongly coregulated with ergosterol biosynthesis. Subsequently, Erg28p was shown to function as an endoplasmic reticulum transmembrane protein, acting as a scaffold to tether the C-4 demethylation enzymatic complex and also to interact with a downstream enzyme, Erg6p. To understand all possible protein interactions involving Erg28p in sterol biosynthesis, a yeast two-hybrid system designed to assess interactions between membrane proteins was used.