Project description:We performed label-free proteomics in C. elegans to define and quantify changes in the ubiquitinated (Ub)-proteome during the aging process. More specifically, we compared wild-type worms at the first day of adulthood with young (day 5), mid-age (day 10) and aged adults (day 15). Moreover, we assessed protein levels of age-matched long-lived genetic models of dietary restriction (eat-2(ad1116)) and reduced insulin/IGF-1 signaling (daf-2(e1370)).
Project description:We performed diGLY enrichment followed by label-free proteomics in C. elegans to define and quantify changes in the ubiquitinated (Ub)-proteome during the aging process. More specifically, we compared wild-type worms at the first day of adulthood with young (day 5), mid-age (day 10) and aged adults (day 15). Moreover, we assessed the Ub-modified proteome of age-matched long-lived genetic models of dietary restriction (eat-2(ad1116)) and reduced reduced insulin/IGF-1 signaling (daf-2(e1370)).
Project description:Notch signaling is a core patterning module for vascular morphogenesis, which co-determines the sprouting behaviour of endothelial cells (ECs). Tight quantitative and temporal control of Notch activity is essential for vascular development, yet the details of Notch regulation in ECs are incompletely understood. We found that ubiquitin-specific peptidase 10 (USP10) interacted with the NOTCH1 intracellular domain (NICD1) to slow the ubiquitin-dependent turnover of this short-lived form of the activated NOTCH1 receptor. Accordingly, inactivation of USP10 reduced NICD1 abundance and stability, and diminished Notch-induced target gene expression in ECs. In mice, loss of endothelial Usp10 increased vessel sprouting and partially restored the patterning defects caused by ectopic expression of NICD1. Thus, USP10 functions as an NICD1 deubiquitinase, which fine-tunes endothelial Notch responses during angiogenic sprouting.
Project description:Ectopic lipid deposition and altered mitochondrial dynamics contribute to the development of obesity and insulin resistance. However, the mechanistic link between both processes remains unclear. Here we demonstrate that abrogation of ceramide synthase (CerS)6, which generates C16:0-sphingolipids, but not of the alternative C16:0-sphingolipid synthetizing CerS5 protects from obesity and insulin resistance, and both enzymes regulate C16:0-sphingolipid synthesis in distinct intracellular compartments. Moreover, we identify proteins, which specifically interact with C16:0-sphingolipids derived from CerS5 or CerS6. Here, only CerS6-derived C16:0-sphingolipids bind the mitochondrial fission factor (Mff). CerS6- and Mff-deficiency protects from fatty acid-induced mitochondrial fragmentation in vitro, and both proteins genetically interact in vivo in obesity-induced mitochondrial fragmentation and development of insulin resistance. Our experiments reveal an unprecedented specificity of sphingolipid-signaling depending on specific synthetizing enzymes, provide a mechanistic link between lipid deposition and mitochondrial dynamics in obesity, and define the CerS6/sphingolid/Mff interaction as a therapeutic target for obesity and diabetes.
Project description:In this project we asked how reducing the activity of the insulin/IGF signaling (IIS) cascade by knocking down the expression of daf-2, affects global protein SUMOylation of C. elegans. We found that among other proteins, IIS reduction lowers the SUMOylation of CAR-1, a protein that negatively regulates the activity of the worm’s notch receptor, GLP-1. Thus, the knockdown of car-1 hyper-activates GLP-1, shortens lifespan and exposes the worm to toxic protein aggregation (proteotoxicity). In contrast, the expression of a SUMOylation resistant CAR-1 (K185R) promotes longevity and protects model nematodes from proteotoxicity.
Project description:We present a comparative analysis of sex-specific tegument proteins of paired or virgin Schistosoma mansoni. By apply a new and highly sensitive workflow, detection of even low abundance proteins from the worm was achieved Therefore, a streptavidin-biotin affinity purification technique in combination with single pot solid-phase enhanced sample preparation was established for subsequent LC-MS/MS analysis. We were able to identify 1519 tegument proteins for male and female as to virgin and paired worms. Sex-specific proteins were screened, present in both virgin and paired adult schistosomes to reduce the impact of mating. Bioinformatic analysis revealed an involvement of female-specific tegument proteins in signaling pathways of cellular processes and antioxidant mechanisms. Male-specific proteins were found to be enriched in processes linked to phosphorylation and signal transduction. This suggests a task sharing between the sexes that might be necessary for survival in the host. Our datasets provide a basis for further studies to understand and ultimately decipher the strategies of the two worm sexes to evade the immune system.
Project description:Pyruvate oxidase encoded by spxB is a major virulence factor in the human respiratory pathogen Streptococcus pneumoniae. During aerobic growth, SpxB synthesizes large amounts of H2O2 and acetyl phosphate, which can serve as a phosphoryl group donor to response regulators and be converted to ATP. SpxB is the main source of the millimolar concentrations of H2O2 produced and tolerated by pneumococcus, despite its lack of a catalase. We report here the first cis- and trans-acting regulatory elements for spxB transcription. These elements were identified in a genetic screen, similar to those used previously for phase variants, for spontaneous mutations that caused colonies of virulent serotype 2 strain D39 to change from a transparent to an opaque appearance. Six of the seven opaque colonies recovered (frequency of 3 x 10-5) were impaired for SpxB function. Modeling suggested that two mutations changed amino acids in SpxB required for FAD cofactor or subunit binding. One mutation deleted a cis-acting adjacent direct repeat required for optimal spxB transcription. The other three independent mutations created the same frameshift near the start of a trans-acting regulatory gene designated as spxR. The SpxR protein contains helix-turn-helix, CBS, and HotDog domains implicated in DNA, adenosine, and CoA compound binding, respectively, consistent with the idea that SpxR positively regulates spxB transcript amount in response to energy and metabolic state rather than oxidative state. Finally, microarray analyses of a null spxB or a spxR mutant revealed the presence of a new oxidative stress response in pneumococcus and unexpectedly demonstrated that SpxR strongly positively regulates the transcript amount of the strH exoglycosidase gene, which like spxB, has been implicated in host colonization. Keywords: genetic modification Bacterial strains were grown exponentially in rich (BHI) media at 37C and an atmosphere of 5% CO2, and were processed as described in the related Sample records. Samples were collected from three independent biological replicates and included one dye swap. Data were normalized using the Lowess (subgrid) method without background subtraction.
Project description:Dietary restriction (DR) is the most effective and reproducible intervention to extend lifespan in divergent species1. In mammals, two regimens of DR, intermittent fasting (IF) and caloric restriction (CR), have proven to extend lifespan and reduce the incidence of age-related disorders2. An important characteristic of IF is that it can increase lifespan, even when there is little or no overall decrease in calorie intake2. The molecular mechanisms underlying IF-induced longevity, however, remain largely unknown. Here we establish an IF regimen that effectively extends the lifespan of Caenorhabditis elegans, and show that a nutrient-related signalling molecule, the low molecular weight GTPase Cel-Rheb, has a dual role in lifespan regulation; Cel-Rheb is required for the IF-induced longevity, whereas inhibition of Cel-Rheb mimics the CR effects. We also show that Cel-Rheb exerts its effects in part via the insulin/IGF-like signalling effector DAF-16 in IF, and that Cel-Rheb is required for fasting-induced nuclear translocation of DAF-16. We find that HSP-12.6, a DAF-16 target, functions to mediate the IF-induced longevity. Furthermore, our analyses demonstrate that most of fasting-induced upregulated genes require Cel-Rheb function for their induction, and that Cel-Rheb/Cel-TOR signalling is required for the fasting-induced downregulation of an insulin-like peptide, INS-7. These findings identify the essential role of signalling via Cel-Rheb in IF-induced longevity and gene expression changes, and suggest a molecular link between the IF-induced longevity and the insulin/IGF-like signalling pathway. Experiment Overall Design: We examined fasting-induced changes of the gene expression profiles in Caenorhabditis elegans. We performed the genome-wide analysis by using Affymetrix GeneChip oligonucleotide microarrays, and examined the effect of downregulation of Cel-Rheb and Cel-TOR by RNAi on the expression profiles. Five independent experiments were performed with wild type N2. Synchronized worms under six conditions (control-fed, control-fasting, Rheb RNAi-fed, Rheb RNAi-fasting, TOR RNAi-fed, and TOR RNAi-fasting) were collected and frozen with liquid nitrogen at day 4 of adulthood. Total RNA was extracted with Sepasol(R)-RNA â Super (Nacalai tesque), and purified with RNeasy Mini Kit (Qiagen), according to manufactureâs instructions. Synthesis of cDNA, in vitro transcription and biotin labelling cRNA, and hybridization to the C. elegans Genome Array (Affymetrix) were performed according to Affymetrix protocols. Hybridized arrays were scanned using an Affymetrix GeneChip Scanner. Scanned chip images were analyzed with GeneSpring GX 7.3.1 (Agilent Technologies).
Project description:To screen the microRNA regulated by Twist1 and Bmi1 Establish stable transfectants of pSUPER-sh-Twist1 or pSUPER-sh-Bmi1 in OECM1 cells and analyze the miRNA expression level of by microRNA microarray. OECM1 transfected with pSUPER-sh-scr was used as a control experiment.