Intracellular transport of a heterologous membrane protein, the human transferrin receptor, in Saccharomyces cerevisiae

We have analyzed the intracellular behavior of the human transferrin receptor (TfR) in Saccharomyces cerevisiae. The major part of the heterologously expressed TfR, which has previously been used as a model for heterologous expression of membrane proteins in yeast, is localized in the endoplasmic reticulum (ER) membranes; a minor fraction is present in the plasma membrane (PM). The stability of the TfR depends on vacuolar proteases, implying that it is degraded in the vacuolar compartment. Degradation is further dependent on favorable transport conditions to this compartment. The main bottleneck of transport seems to be the transition from the ER to the PM. The chaperone Cne1p, which is involved in quality control in the ER, plays a role in regulating the amount of heterologous TfR, as deletion of CNE1 leads to significant accumulation of the protein. This is the first demonstration of the involvement of CNE1 in regulating the level of heterologous membrane proteins

Increasing the Business Value Of Free-Floating Carsharing Fleets By Applying Machine-Learning Based Relocations

Free-floating carsharing (CS) services provide customers with a fleet of vehicles distributed within an operation area. These services gained popularity because of their positive impact on societal and personal mobility. Understanding determinants of customer demand is a key challenge for developing and applying vehicle relocation strategies to prevent the formation of undersupply areas. In this study, we merge possible features from publicly available data sources with historical demand from CS services situated in three different-sized cities. We train and test a Random Forest (RF) regressor estimating demand based on the enhanced dataset. Building on this demand prediction, we developed a relocation strategy that optimizes vehicle availability at anticipated demand points. Our strategy improved the reservation acceptance ratio in all three reference systems between 7.1 % and 15.6 %. Furthermore, the number of relocations compared to a deterministic relocation strategy could be reduced by 82.3 % and 20.6 % in two cities

Control of Signaling in a MAP-kinase Pathway by an RNA-Binding Protein

Signaling-protein mRNAs tend to have long untranslated regions (UTRs) containing binding sites for RNA-binding proteins regulating gene expression. Here we show that a PUF-family RNA-binding protein, Mpt5, represses the yeast MAP-kinase pathway controlling differentiation to the filamentous form. Mpt5 represses the protein levels of two pathway components, the Ste7 MAP-kinase kinase and the Tec1 transcriptional activator, and negatively regulates the kinase activity of the Kss1 MAP kinase. Moreover, Mpt5 specifically inhibits the output of the pathway in the absence of stimuli, and thereby prevents inappropriate cell differentiation. The results provide an example of what may be a genome-scale level of regulation at the interface of signaling networks and protein-RNA binding networks

Leadership skills of principals. Development of a prototypical competence model

Der Beitrag zeigt auf, inwieweit sich aus neuen Herausforderungen für Schulleitungen zusätzliche Kompetenzbedarfe im Bereich Führung ergeben. Aus der Diskussion zweier prominenter Führungsmodelle und den Ergebnissen der interdisziplinären Kompetenzforschung wird ein prototypisches Kompetenzmodell für Schulleitungen entwickelt. Die Anforderungen werden auf Basis faktorenanalytisch fundierter Dimensionen geordnet. Das Ziel besteht in einer verbesserten Auswahl und Entwicklung von Schulleitungen. (DIPF/Orig)The increased requirements at schools have also enlarged the range of management responsibilities. Two prominent models of school management are discussed. A prototypical model of competency for school management is evolved from the models\u27 discussion and the results of the interdisciplinary research on competency. The competency demands are arranged on basis of two dimensions derived from factor analysis. The developed model provides a framework for an improved selection and development of school management. (DIPF/Orig.

Induction of inhibitory central nervous system-derived and stimulatory blood-derived dendritic cells suggests a dual role for granulocyte-macrophage colony-stimulating factor in central nervous system inflammation

The mononuclear phagocyte system, particularly dendritic cells, plays several pivotal roles in the development of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis. Here, we demonstrate that functionally distinct dendritic cell subpopulations are present in the central nervous system during experimental autoimmune encephalomyelitis. At peak experimental autoimmune encephalomyelitis, the majority of dendritic cells consisted of a CD11b+F4/80+ inflammatory dendritic cell subtype. Both granulocyte-macrophage colony-stimulating factor and chemokine (C-C motif) ligand 2 were previously suggested to recruit ‘inflammatory' monocyte-derived dendritic cells to the central nervous system during experimental autoimmune encephalomyelitis. We show that intra-cerebral production of granulocyte-macrophage colony-stimulating factor leading to chemokine (C-C motif) ligand 2 induction and attraction of chemokine (C-C motif) receptor 2-positive precursors suffices to recruit dendritic cell populations identical to those observed in experimental autoimmune encephalomyelitis into the central nervous system of healthy mice. This does not occur with fms-like tyrosine kinase-3-ligand treatment. Both during experimental autoimmune encephalomyelitis and upon intra-cerebral granulocyte-macrophage colony-stimulating factor production, all myeloid dendritic cells, lymphoid dendritic cells and periphery-derived inflammatory dendritic cells stimulated T cell proliferation, whereas inflammatory dendritic cells that differentiated from central nervous system precursors inhibited T cell activation and pro-inflammatory cytokine production. Despite the capacity of granulocyte-macrophage colony-stimulating factor to induce central nervous system-derived inhibitory inflammatory dendritic cells, the administration of granulocyte-macrophage colony-stimulating factor into mice with experimental autoimmune encephalomyelitis resulted in exacerbated disease. Granulocyte-macrophage colony-stimulating factor thus has a dual role in the central nervous system: it directs both central nervous system-derived dendritic cells towards an inhibitory phenotype and recruits peripheral dendritic cells exhibiting pro-inflammatory function

Prediction of phenotype and gene expression for combinations of mutations

Molecular interactions provide paths for information flows. Genetic interactions reveal active information flows and reflect their functional consequences. We integrated these complementary data types to model the transcription network controlling cell differentiation in yeast. Genetic interactions were inferred from linear decomposition of gene expression data and were used to direct the construction of a molecular interaction network mediating these genetic effects. This network included both known and novel regulatory influences, and predicted genetic interactions. For corresponding combinations of mutations, the network model predicted quantitative gene expression profiles and precise phenotypic effects. Multiple predictions were tested and verified

Effect of Topically Administered Chitosan- N

Purpose. The present study was performed to investigate the effect of topically administered chitosan-N-acetylcysteine (C-NAC) on corneal wound healing in a rabbit model. Methods. A total of 20 New Zealand White rabbits were included in the randomized, masked, placebo-controlled experiment. A monocular epithelial debridement was induced by manual scraping under general anesthesia. Animals were randomized to receive either C-NAC two times daily or placebo. Monitoring of corneal wound healing was performed with ultra-high-resolution optical coherence tomography (OCT) and epithelial fluorescein staining. Measurements were done immediately after and up to 72 hours after wound induction. Results. No difference in wound size was found immediately after surgical debridement between the C-NAC group and the placebo group. Wound healing was significantly faster in the C-NAC group compared to the placebo group (p<0.01 for both methods). A good correlation was found between the OCT technique and the epithelial fluorescein staining in terms of wound size (r=0.94). Conclusions. Administration of C-NAC containing eye drops twice daily leads to a faster corneal wound healing in a rabbit model of corneal debridement as compared to placebo. Ultra-high-resolution OCT is considered a noninvasive, dye-free alternative to conventional fluorescein staining in assessing corneal wound healing also in humans

Gammaretrovirus-mediated correction of SCID-X1 is associated with skewed vector integration site distribution in vivo

We treated 10 children with X-linked SCID (SCID-X1) using gammaretrovirus-mediated gene transfer. Those with sufficient follow-up were found to have recovered substantial immunity in the absence of any serious adverse events up to 5 years after treatment. To determine the influence of vector integration on lymphoid reconstitution, we compared retroviral integration sites (RISs) from peripheral blood CD3(+) T lymphocytes of 5 patients taken between 9 and 30 months after transplantation with transduced CD34(+) progenitor cells derived from 1 further patient and I healthy donor. Integration occurred preferentially in gene regions on either side of transcription start sites, was clustered, and correlated with the expression level in CD34(+) progenitors during transduction. In contrast to those in CD34(+) cells, RISs recovered from engrafted CD3(+)T cells were significantly overrepresented within or near genes encoding proteins with kinase or transferase activity or involved in phosphorus metabolism. Although gross patterns of gene expression were unchanged in transduced cells, the divergence of RIS target frequency between transduced progenitor cells and post-thymic T lymphocytes indicates that vector integration influences cell survival, engraftment, or proliferation