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Rab11-FIP3 is critical for the structural integrity of the endosomal recycling compartment 总被引:2,自引:0,他引:2
Horgan CP Oleksy A Zhdanov AV Lall PY White IJ Khan AR Futter CE McCaffrey JG McCaffrey MW 《Traffic (Copenhagen, Denmark)》2007,8(4):414-430
Rab11-FIP3 is an endosomal recycling compartment (ERC) protein that is implicated in the process of membrane delivery from the ERC to sites of membrane insertion during cell division. Here we report that Rab11-FIP3 is critical for the structural integrity of the ERC during interphase. We demonstrate that knockdown of Rab11-FIP3 and expression of a mutant of Rab11-FIP3 that is Rab11-binding deficient cause loss of all ERC-marker protein staining from the pericentrosomal region of A431 cells. Furthermore, we find that fluorophore-labelled transferrin cannot access the pericentrosomal region of cells in which Rab11-FIP3 function has been perturbed. We find that this Rab11-FIP3 function appears to be specific because expression of the equivalent Rab11-binding deficient mutant of Rab-coupling protein does not perturb ERC morphology. In addition, we find that other organelles such as sorting and late endosomes are unaffected by loss of Rab11-FIP3 function. Finally, we demonstrate the presence of an extensive coiled-coil region between residues 463 and 692 of Rab11-FIP3, which exists as a dimer in solution and is critical to support its function on the ERC. Together, these data indicate that Rab11-FIP3 is necessary for the structural integrity of the pericentrosomal ERC. 相似文献
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The past several years have witnessed the emergence of a new world of nucleic-acid-based architectures with highly predictable and programmable self-assembly properties. For almost two decades, DNA has been the primary material for nucleic acid nanoconstruction. More recently, the dramatic increase in RNA structural information led to the development of RNA architectonics, the scientific study of the principles of RNA architecture with the aim of constructing RNA nanostructures of any arbitrary size and shape. The remarkable modularity and the distinct but complementary nature of RNA and DNA nanomaterials are revealed by the various self-assembly strategies that aim to achieve control of the arrangement of matter at a nanoscale level. 相似文献
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Rafał Wcisło Witold Dzwinel David A. Yuen Arkadiusz Z. Dudek 《Journal of molecular modeling》2009,15(12):1517-1539
The dynamics of a growing tumor involving mechanical remodeling of healthy tissue and vasculature is neglected in most of
the existing tumor models. This is due to the lack of efficient computational framework allowing for simulation of mechanical
interactions. Meanwhile, just these interactions trigger critical changes in tumor growth dynamics and are responsible for
its volumetric and directional progression. We describe here a novel 3-D model of tumor growth, which combines particle dynamics
with cellular automata concept. The particles represent both tissue cells and fragments of the vascular network. They interact
with their closest neighbors via semi-harmonic central forces simulating mechanical resistance of the cell walls. The particle dynamics is governed by both
the Newtonian laws of motion and the cellular automata rules. These rules can represent cell life-cycle and other biological
interactions involving smaller spatio-temporal scales. We show that our complex automata, particle based model can reproduce
realistic 3-D dynamics of the entire system consisting of the tumor, normal tissue cells, blood vessels and blood flow. It
can explain phenomena such as the inward cell motion in avascular tumor, stabilization of tumor growth by the external pressure,
tumor vascularization due to the process of angiogenesis, trapping of healthy cells by invading tumor, and influence of external
(boundary) conditions on the direction of tumor progression. We conclude that the particle model can serve as a general framework
for designing advanced multiscale models of tumor dynamics and it is very competitive to the modeling approaches presented
before. 相似文献
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Maja ?ebska Arkadiusz Ciesielski Lidia Szymona Luiza Godecka El?bieta Lewandowska-Gnatowska Jadwiga Szczegielniak Gra?yna Muszyńska 《The Journal of biological chemistry》2010,285(9):6217-6226
Maize eukaryotic translation initiation factor 5A (ZmeIF5A) co-purifies with the catalytic α subunit of protein kinase CK2 and is phosphorylated by this enzyme. Phosphorylated ZmeIF5A was also identified after separation of maize leaf proteins by two-dimensional electrophoresis. Multiple sequence alignment of eIF5A proteins showed that in monocots, in contrast to other eukaryotes, there are two serine/threonine residues that could potentially be phosphorylated by CK2. To identify the phosphorylation site(s) of ZmeIF5A, the serine residues potentially phosphorylated by CK2 were mutated. ZmeIF5A and its mutated variants S2A and S4A were expressed in Escherichia coli and purified. Of these recombinant proteins, only ZmeIF5A-S2A was not phosphorylated by maize CK2. Also, Arabidopsis thaliana and Saccharomyces cerevisiae eIF5A-S2A mutants were not phosphorylated despite effective phosphorylation of wild-type variants. A newly developed method exploiting the specificity of thrombin cleavage was used to confirm that Ser2 in ZmeIF5A is indeed phosphorylated. To find a role of the Ser2 phosphorylation, ZmeIF5A and its variants mutated at Ser2 (S2A and S2D) were transiently expressed in maize protoplasts. The expressed fluorescence labeled proteins were visualized by confocal microscopy. Although wild-type ZmeIF5A and its S2A variant were distributed evenly between the nucleus and cytoplasm, the variant with Ser2 replaced by aspartic acid, which mimics a phosphorylated serine, was sequestered in the nucleus. These results suggests that phosphorylation of Ser2 plays a role in regulation of nucleocytoplasmic shuttling of eIF5A in plant cells. 相似文献
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A comparison of the in vitro antimicrobial activity of liposomes containing meropenem and gentamicin
Drulis-Kawa Z Gubernator J Dorotkiewicz-Jach A Doroszkiewicz W Kozubek A 《Cellular & molecular biology letters》2006,11(3):360-375
The antimicrobial activity of eight cationic, two neutral and three anionic liposome compositions containing meropenem and
gentamicin was tested in vitro in broth and serum medium. The cationic formulations showed better antibacterial efficacy against both Gram-positive and
Gram-negative bacteria than the anionic and neutral ones, regardless of the encapsulated drug. The most effective formulations
were the cationic PC/DOPE/DOTAP 3:4:3 and PC/Chol/DOTAP 3:4:3, as the MICs with meropenem were 2 to 4 times lower than those
of the free drug. 相似文献
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Chih-Li Wang Arkadiusz Malkus Sabina M Zuzga Pi-Fang Linda Chang Barry M Cunfer Edward Arseniuk Peter P Ueng 《Génome》2007,50(6):595-609
Phaeosphaeria species are important causal agents of Stagonospora leaf blotch diseases in cereals. In this study, the nucleotide sequence and deduced polypeptide of the trifunctional histidine biosynthesis gene (his) are used to investigate the phylogenetic relationships and provide molecular identification among cereal Phaeosphaeria species. The full-length sequences of the his gene were obtained by PCR amplification and compared among cereal Phaeosphaeria species. The coding sequence of the his gene in wheat-biotype P. nodorum (PN-w) was 2697 bp. The his genes in barley-biotype P. nodorum (PN-b), two P. avenaria f. sp. triticea isolates (homothallic Pat1 and Pat3), and Phaeosphaeria species from Polish rye and dallis grass were 2694 bp. The his gene in heterothallic isolate Pat2, however, was 2693 bp because the intron had one fewer base. In P. avenaria f. sp. avenaria (Paa), the his gene was only 2670 bp long. The differences in the size of the his gene contributed to the variation in amino acid sequences in the gap region located between the phosphoribosyl-ATP pyrophosphohydrolase and histidinol dehydrogenase sub-domains. Based on nucleotide and deduced amino acid sequences of the his gene, Pat1 was not closely related to either PN-w or the Paa clade. It appears that rates of evolution of the his gene were fast in cereal Phaeosphaeria species. The possible involvement of meiotic recombination in genetic diversity of the his gene in P. nodorum is discussed. 相似文献
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