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71.
Phosphatidylethanolamine critically supports internalization of cell-penetrating protein C inhibitor 下载免费PDF全文
Baumgärtner P Geiger M Zieseniss S Malleier J Huntington JA Hochrainer K Bielek E Stoeckelhuber M Lauber K Scherfeld D Schwille P Wäldele K Beyer K Engelmann B 《The Journal of cell biology》2007,179(4):793-804
Although their contribution remains unclear, lipids may facilitate noncanonical routes of protein internalization into cells such as those used by cell-penetrating proteins. We show that protein C inhibitor (PCI), a serine protease inhibitor (serpin), rapidly transverses the plasma membrane, which persists at low temperatures and enables its nuclear targeting in vitro and in vivo. Cell membrane translocation of PCI necessarily requires phosphatidylethanolamine (PE). In parallel, PCI acts as a lipid transferase for PE. The internalized serpin promotes phagocytosis of bacteria, thus suggesting a function in host defense. Membrane insertion of PCI depends on the conical shape of PE and is associated with the formation of restricted aqueous compartments within the membrane. Gain- and loss-of-function mutations indicate that the transmembrane passage of PCI requires a branched cavity between its helices H and D, which, according to docking studies, precisely accommodates PE. Our findings show that its specific shape enables cell surface PE to drive plasma membrane translocation of cell-penetrating PCI. 相似文献
72.
Katja Zschiebsch Caroline Fischer Annett Wilken‐Schmitz Gerd Geisslinger Keith Channon Katrin Watschinger Irmgard Tegeder 《Journal of cellular and molecular medicine》2019,23(2):985-1000
GTP cyclohydrolase (GCH1) governs de novo synthesis of the enzyme cofactor, tetrahydrobiopterin (BH4), which is essential for biogenic amine production, bioactive lipid metabolism and redox coupling of nitric oxide synthases. Overproduction of BH4 via upregulation of GCH1 in sensory neurons is associated with nociceptive hypersensitivity in rodents, and neuron‐specific GCH1 deletion normalizes nociception. The translational relevance is revealed by protective polymorphisms of GCH1 in humans, which are associated with a reduced chronic pain. Because myeloid cells constitute a major non‐neuronal source of BH4 that may contribute to BH4‐dependent phenotypes, we studied here the contribution of myeloid‐derived BH4 to pain and itch in lysozyme M Cre‐mediated GCH1 knockout (LysM‐GCH1?/?) and overexpressing mice (LysM‐GCH1‐HA). Unexpectedly, knockout or overexpression in myeloid cells had no effect on nociceptive behaviour, but LysM‐driven GCH1 knockout reduced, and its overexpression increased the scratching response in Compound 48/80 and hydroxychloroquine‐evoked itch models, which involve histamine and non‐histamine dependent signalling pathways. Mechanistically, GCH1 overexpression increased BH4, nitric oxide and hydrogen peroxide, and these changes were associated with increased release of histamine and serotonin and degranulation of mast cells. LysM‐driven GCH1 knockout had opposite effects, and pharmacologic inhibition of GCH1 provided even stronger itch suppression. Inversely, intradermal BH4 provoked scratching behaviour in vivo and BH4 evoked an influx of calcium in sensory neurons. Together, these loss‐ and gain‐of‐function experiments suggest that itch in mice is contributed by BH4 release plus BH4‐driven mediator release from myeloid immune cells, which leads to activation of itch‐responsive sensory neurons. 相似文献
73.
Wipf D Ludewig U Tegeder M Rentsch D Koch W Frommer WB 《Trends in biochemical sciences》2002,27(3):139-147
When comparing the transporters of three completely sequenced eukaryotic genomes--Saccharomyces cerevisiae, Arabidopsis thaliana and Homo sapiens--transporter types can be distinguished according to phylogeny, substrate spectrum, transport mechanism and cell specificity. The known amino acid transporters belong to five different superfamilies. Two preferentially Na(+)-coupled transporter superfamilies are not represented in the yeast and Arabidopsis genomes, whereas the other three groups, which often function as H(+)-coupled systems, have members in all investigated genomes. Additional superfamilies exist for organellar transport, including mitochondrial and plastidic carriers. When used in combination with phylogenetic analyses, functional comparison might aid our prediction of physiological functions for related but uncharacterized open reading frames. 相似文献
74.
Claus Orendt Georg Wolfram Zdeněk Adámek Pavel Jurajda Mechthild Schmitt-Jansen 《Biologia》2012,67(1):180-199
Macroinvertebrate communities were investigated along a gradient of heavy industrial and municipal pollution in the highland
Bílina River (Czech Republic). Physico-chemical determinants and ions were monitored and community analysis performed focusing
on taxonomic composition, ecological functioning (feeder and dweller guilds) and water quality metrics, including saprobity
index, BMWP and diversity. Impacted sites differed significantly from reference and from recovered stretches. Chemical data
revealed two main pollution factors, (1) a “salinity determinant”, described best by conductivity and SO42−, and (2) an “organic pollution determinant”, represented best by O2 concentrations and NO2−, all varying locally and temporally. Some metrics and taxa showed significant correlations to abiotic parameters. Functional
communities showed a stronger relationship to the “organic pollution determinant”, suggesting that elevated organic pollution
had a dominating influence on functional community metrics; though other variables may also have an influence in this multistress
environment. On the other hand, there were indications that the taxonomic community was more influenced by ion concentrations
(“salinity determinant”). The gradient from reference sites to polluted sites was weaker in the final sampling campaign. The
results presented here can be used as a reference for assessing future changes in environmental impact from pollution, being
finer and more detailed than assessment according to the EU’s WFD. 相似文献
75.
Jana Zschille Norman Stier Mechthild Roth Uta Berger 《European Journal of Wildlife Research》2012,58(6):955-968
Telemetry of American mink Neovison vison revealed seasonal and sexual variations in home-range size, intersexual- and partially intrasexual range overlaps and spatial dynamic of territorial system. From 2003 to 2006, 14 mink (nine males and five females) were radio-tracked in a fishpond area in northern Germany. We observed comparatively large home ranges. Both sexes reduced their large summer home ranges to smaller ones in the winter period. In both seasons, male mink used significantly larger areas than female mink. During the mating season, males considerably enlarged their home ranges and roamed nearly through the entire study area. These variations and diversity of range size were discussed in connection with thermoregulatory behaviour, prey availability and distribution, population density and stability of the social system. Analysing intraspecific static interactions, we observed high intersexual overlapping rates in both the summer and winter periods. But there were no or rather very low levels of intrasexual overlapping. However, in the summer period, large home ranges of neighbouring males also overlapped to some extent, but temporal avoidance of adjacent territory holders was observed. Consequently, our results reveal intrasexual territoriality, with males having larger territories, overlapping those of females. The shifting of stable temporary home ranges observed within one season or between the same seasons of consecutive years demonstrates the highly dynamic nature of spatial behaviour among American mink. All these recorded characteristic features of spatial behaviour should be considered when planning mink control projects and measures for the management of this invasive carnivore. 相似文献
76.
Schroeter MM Beall B Heid HW Chalovich JM 《Biochemical and biophysical research communications》2008,371(3):582-586
Fesselin is a natively unfolded protein that is abundant in avian smooth muscle. Like many natively unfolded proteins, fesselin has multiple binding partners including actin, myosin, calmodulin and α-actinin. Fesselin accelerates actin polymerization and bundles actin. These and other observations suggest that fesselin is a component of the cytoskeleton. We have now cloned fesselin and have determined the cDNA derived amino acid sequence. We verified parts of the sequence by Edman analysis and by mass spectroscopy. Our results confirmed fesselin is homologous to human synaptopodin 2 and belongs to the synaptopodin family of proteins. 相似文献
77.
Oliver Keuling Norman Stier Mechthild Roth 《European Journal of Wildlife Research》2008,54(3):403-412
In a radiotelemetric study, we analysed space use of 24 female specimens (14 family groups and 14 nonreproductive yearling
females) out of 23 wild boar groups for periods between 3 and 39 months. Generally, wild boar used relatively small areas,
showed high site fidelity but also a strong individual variation of home ranges, indicating a high flexibility in space use.
Although age-specific differences were not statistically significant, female yearlings tended to have larger mean annual home
ranges (1,185 ha MCP) than animals ranging in family groups (771 ha). Yearlings also showed a stronger shifting from spring
to summer home ranges (2,345 m) and a tendency towards larger home range sizes in summer (791 ha MCP), compared to family
groups (shift 1,766 m, MCP 461 ha). Yearlings displayed a dislocation of about 1 km of the annual centre in the first year
after dividing from the mother. In contrast, in adults older than 2 years, the dislocation of the annual center was only 240 m. 相似文献
78.
An analysis of the primary structure of the actin-binding protein fesselin revealed it to be the avian homologue of mammalian synaptopodin 2 [Schroeter, Beall, Heid, and Chalovich (2008) Biochem. Biophys. Res. Commun. 371, 582-586]. We isolated two synaptopodin 2 isoforms from rabbit stomach that corresponded to known types of human synaptopodin 2. The purification scheme used was that developed for avian fesselin. These synaptopodin 2 forms shared several key functions with fesselin. Both avian fesselin and mammalian synaptopodin 2 bound to Ca(2+)-calmodulin, alpha-actinin and smooth-muscle myosin. In addition, both proteins stimulated the polymerization of actin in a Ca(2+)-calmodulin-dependent manner. Synaptopodin 2 has never before been shown to polymerize actin in the absence of alpha-actinin, to polymerize actin in a Ca(2+)-calmodulin-dependent manner, or to bind to Ca(2+)-calmodulin or myosin. These properties are consistent with the proposed function of synaptopodin 2 in organizing the cytoskeleton. 相似文献
79.
All‐Solid‐State,Foldable, and Rechargeable Zn‐Air Batteries Based on Manganese Oxide Grown on Graphene‐Coated Carbon Cloth Air Cathode 下载免费PDF全文
Afriyanti Sumboja Mechthild Lübke Yong Wang Tao An Yun Zong Zhaolin Liu 《Liver Transplantation》2017,7(20)
Pliable, safe, and inexpensive energy storage devices are in demand to power modern flexible electronics. In this work, a foldable battery based on a solid‐state and rechargeable Zn‐air battery is introduced. The air cathode is prepared by coating graphene flakes on pretreated carbon cloth to form a dense, interconnected, and conducting carbon network. Manganese oxide hierarchical nanostructures are subsequently grown on the large surface area carbon network, leading to high loading of active catalyst per unit volume while maintaining the mechanical and electrical integrity of the air cathode. Solid‐state and rechargeable Zn‐air battery with such air cathode exhibits similar polarization curve and resistance at its flat and folded states. The folded battery is able to deliver a power density as high as ≈32 mW cm?2 and good cycling stability of up to 110 cycles. In addition, the flat battery shows similar discharge/charge curve and stable cycling performance after 100 times of repeated folding and unfolding, indicating its high mechanical robustness. 相似文献
80.
Mechthild Röhm Wolfgang Streit Harold J. Evans Dietrich Werner 《Trees - Structure and Function》1993,8(2):99-103
Summary Hydrogen uptake is thought to increase the efficiency of nitrogen fixation by recycling H2 produced by nitrogenase that would otherwise be lost by diffusion. Here we demonstrate the capacity of eight Rhizobium strains to take up molecular hydrogen. Uptake by nodule homogenates from Robinia pseudoacacia was measured amperometrically under nitrogenase repression. Markedly lower activities were found than in soybean nodules. In addition hydrogenase activity was detected by the ability of bacteroids to reduce methylene blue in the presence of hydrogen. It was demonstrated that hydrogenase structural genes are present in the black locust symbiont, Rhizobium sp. strain R1, using hybridization with a plasmid, which contained hydrogenase genes from R. leguminosarum bv. viceae. 相似文献