The Retriever complex recycles a wide range of transmembrane proteins from endosomes to the plasma membrane. The cargo adapter protein SNX17 has been implicated in recruiting the Retriever complex to endosomal membranes, yet the details of this interaction have remained elusive. Through biophysical and structural model-guided mutagenesis studies with recombinant proteins and liposomes, we have gained a deeper understanding of this process.
View Article and Find Full Text PDFDuring oncogene-induced senescence there are striking changes in the organisation of heterochromatin in the nucleus. This is accompanied by activation of a pro-inflammatory gene expression programme - the senescence-associated secretory phenotype (SASP) - driven by transcription factors such as NF-κB. The relationship between heterochromatin re-organisation and the SASP has been unclear.
View Article and Find Full Text PDFExplanations for differences in thermal biology within and between species of lizards employ concepts of phylogenetic inertia and plasticity. We compared the thermal biology of three liolaemid species in the Andean highlands in Argentina: two allopatric congeners (Phymaturus williamsi and P. aguanegra) each in syntopy with Liolaemus parvus.
View Article and Find Full Text PDFSeveral human disturbances contribute to the decrease of vertebrate species' richness and abundance, altering the processes of an ecosystem. We evaluate richness, diversity and relative abundance of species for lizard assemblages at sites with different degrees of perturbation in the center-west of the Arid Chaco region in Argentina. Between 2015 and 2018, six lizard assemblages were sampled monthly -using pitfall traps- in three areas of the Chaco, with a perturbed and an unperturbed (control) replica at each of the areas: (1) Chaco Mountain plain, (2) Chaco Mountain slope, and (3) Chaco Plains, and habitat characteristics of each study site were recorded.
View Article and Find Full Text PDFCellular senescence is a stress response involved in ageing and diverse disease processes including cancer, type-2 diabetes, osteoarthritis and viral infection. Despite growing interest in targeted elimination of senescent cells, only few senolytics are known due to the lack of well-characterised molecular targets. Here, we report the discovery of three senolytics using cost-effective machine learning algorithms trained solely on published data.
View Article and Find Full Text PDFInhibition of the electron transport chain (ETC) prevents the regeneration of mitochondrial NAD, resulting in cessation of the oxidative tricarboxylic acid (TCA) cycle and a consequent dependence upon reductive carboxylation for aspartate synthesis. NAD regeneration alone in the cytosol can rescue the viability of ETC-deficient cells. Yet, how this occurs and whether transfer of oxidative equivalents to the mitochondrion is required remain unknown.
View Article and Find Full Text PDFUnlabelled: Intrahepatic cholangiocarcinoma (ICC) is an aggressive malignancy of the bile ducts within the liver characterized by high levels of genetic heterogeneity. In the context of such genetic variability, determining which oncogenic mutations drive ICC growth has been difficult, and developing modes of patient stratification and targeted therapies remains challenging. Here we model the interactions between rare mutations with more common driver genes and combine in silico analysis of patient data with highly multiplexed in vivo CRISPR-spCas9 screens to perform a functional in vivo study into the role genetic heterogeneity plays in driving ICC.
View Article and Find Full Text PDFFunctional traits are those characteristics of organisms that influence the ability of a species to develop in a habitat and persist in the face of environmental changes. The traits are often affected by a multiplicity of species-dependent and external factors. Our objective was to investigate thermal biology of Liolaemus ruibali in a high altitude cold desert at the arid Puna region, Argentina.
View Article and Find Full Text PDFCytoplasmic recognition of microbial lipopolysaccharides (LPS) in human cells is elicited by the caspase-4 and caspase-5 noncanonical inflammasomes, which induce a form of inflammatory cell death termed pyroptosis. Here we show that LPS-mediated activation of caspase-4 also induces a stress response promoting cellular senescence, which is dependent on the caspase-4 substrate gasdermin-D and the tumor suppressor p53. Furthermore, we found that the caspase-4 noncanonical inflammasome is induced and assembled in response to oncogenic RAS signaling during oncogene-induced senescence (OIS).
View Article and Find Full Text PDFReptiles are important models for understanding fundamental aspects of physiological ecology and for assessing how environmental change can impact biodiversity. Abiotic factors (micro-environmental temperatures, operative temperatures, thermal quality) may vary geographically along an altitudinal and latitudinal gradient, and therefore the different thermal resources available for thermoregulation also vary. Comparative analyses among populations provide an opportunity to understand how variation in abiotic factors can affect different ecophysiological traits of a species at different geographical points.
View Article and Find Full Text PDFWith the ongoing COVID-19 (Coronavirus Disease 2019) pandemic, caused by the novel coronavirus SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), there is a need for sensitive, specific, and affordable diagnostic tests to identify infected individuals, not all of whom are symptomatic. The most sensitive test involves the detection of viral RNA using RT-qPCR (quantitative reverse transcription PCR), with many commercial kits now available for this purpose. However, these are expensive, and supply of such kits in sufficient numbers cannot always be guaranteed.
View Article and Find Full Text PDFCellular senescence is a stress response program characterized by a robust cell cycle arrest and the induction of a proinflammatory senescence-associated secretory phenotype (SASP) that is triggered through an unknown mechanism. Here, we show that, during oncogene-induced senescence (OIS), the Toll-like receptor 2 (TLR2) and its partner TLR10 are key mediators of senescence in vitro and in murine models. TLR2 promotes cell cycle arrest by regulating the tumor suppressors p53-p21, p16, and p15 and regulates the SASP through the induction of the acute-phase serum amyloids A1 and A2 (A-SAAs) that, in turn, function as the damage-associated molecular patterns (DAMPs) signaling through TLR2 in OIS.
View Article and Find Full Text PDFCellular senescence is triggered by diverse stimuli and is characterized by long-term growth arrest and secretion of cytokines and chemokines (termed the SASP-senescence-associated secretory phenotype). Senescence can be organismally beneficial as it can prevent the propagation of damaged or mutated clones and stimulate their clearance by immune cells. However, it has recently become clear that senescence also contributes to the pathophysiology of aging through the accumulation of damaged cells within tissues.
View Article and Find Full Text PDFDuring oncogene-induced senescence (OIS), heterochromatin is lost from the nuclear periphery and forms internal senescence-associated heterochromatin foci (SAHFs). We show that an increased nuclear pore density during OIS is responsible for SAHF formation. In particular, the nucleoporin TPR is necessary for both formation and maintenance of SAHFs.
View Article and Find Full Text PDFInflammasomes are multimeric protein complexes that process IL-1β by cleaving the translated full-length protein into its active IL-1β mature fragment. In oncogene-induced senescence, inflammasomes play a crucial role by regulating IL1R signaling and consequently modulating proliferation and the senescence-associated secretory phenotype (SASP). Inflammasome activation requires two steps: (a) priming of the inflammasome by activation of IL1B expression, followed by (b) cleavage and release of mature IL-1β.
View Article and Find Full Text PDFLocomotion is relevant to the ecology of reptiles because of its presumed influence on an organism's Darwinian fitness. Moreover, in ectothermic species, physiological performance capacity is affected by body temperature. We analyzed two components of locomotor performance in three species of lizards, Phymaturus extrilidus, Liolaemus parvus, and Liolaemus ruibali, in the Puna environment of Argentina.
View Article and Find Full Text PDFCellular p53 protein levels are regulated by a ubiquitination/de-ubiquitination cycle that can target the protein for proteasomal destruction. The ubiquitination reaction is catalyzed by a multitude of ligases, whereas the removal of ubiquitin chains is mediated by two deubiquitinating enzymes (DUBs), USP7 (HAUSP) and USP10. Here, we show that PHD3 hydroxylates p53 at proline 359, a residue that is in the p53-DUB binding domain.
View Article and Find Full Text PDFThe pattern of infection with the nematode Parapharyngodon riojensis in the lizard Phymaturus extrilidus in a Puna area, central-west Argentina was studied. No significant prevalence differences were found between sexes or seasons sampled. However, there were differences in mean intensity between the summer (dry period) and autumn (wet period) seasons.
View Article and Find Full Text PDFCellular senescence is a mechanism that provides an irreversible barrier to cell cycle progression to prevent undesired proliferation. However, under pathological circumstances, senescence can adversely affect organ function, viability and regeneration. We have developed a mouse model of biliary senescence, based on the conditional deletion of Mdm2 in bile ducts under the control of the Krt19 promoter, that exhibits features of biliary disease.
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