Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • PROTEIN  (10)
  • 1
    Keywords: CELLS ; tumor ; CELL ; Germany ; human ; SYSTEM ; PROTEIN ; PATIENT ; MATURATION ; ACID ; ACIDS ; TRANSPORT ; IDENTIFICATION ; resistance ; PLASMA ; MEMBRANE ; MUTATION ; LOCALIZATION ; EXCHANGE ; PLASMA-MEMBRANE ; DEGRADATION ; HEPATOCYTE CANALICULAR ISOFORM ; AMINO-ACIDS ; QUANTITATIVE-ANALYSIS ; DRUG-RESISTANCE ; MULTIDRUG-RESISTANCE ; ABCC2 ; ATP-dependent transport ; CONJUGATE EXPORT PUMP ; deficient protein maturation ; ENDOPLASMIC-RETICULUM ; GENE CAUSES ; HEPG2 CELLS ; MRP2 ; multidrug resistance protein 2 ; MULTIDRUG-RESISTANCE PROTEIN-2 ; ORGANIC ANION-TRANSPORTER ; protein trafficking ; SUBSTRATE-SPECIFICITY
    Abstract: Absence of a functional multidrug resistance protein 2 (MRP2; symbol ABCC2) from the hepatocyte canalicular membrane is the molecular basis of Dubin-Johnson syndrome, an inherited disorder associated with conjugated hyperbilirubinemia in humans. In this work, we analyzed a relatively frequent Dubin- Johnson syndrome mutation that leads to an exchange of two hydrophobic amino acids, isoleucine 1173 to phenylalanine (MRP2I1173F), in a predicted extracellular loop of MRP2. HEK- 293 cells stably transfected with MRP2I1173F cDNA synthesized a mutant protein that was mainly core-glycosylated, predominantly retained in the endoplasmic reticulum, and degraded by proteasomes. MRP2I1173F did not mediate ATP-dependent transport of leukotriene C-4 (LTC4) into vesicles from plasma membrane and endoplasmic reticulum preparations while normal MRP2 was functionally active. Human HepG2 cells were used to study localization of MRP2I1173F in a polarized cell system. Quantitative analysis showed that GFP-tagged MRP2I1173F was localized to the apical membrane in only 5% of transfected, polarized HepG2 cells compared with 80% for normal MRP2-GFP. Impaired protein maturation followed by proteasomal degradation of inactive MRP2I1173F explain the deficient hepatobiliary elimination observed in this group of Dubin-Johnson syndrome patients
    Type of Publication: Journal article published
    PubMed ID: 12388192
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    Keywords: CELLS ; Germany ; PROTEIN ; PROTEINS ; METABOLISM ; desmosome ; COMPLEX ; COMPLEXES ; MESSENGER-RNA ; FAMILY ; BINDING ; PARTICLES ; IDENTIFICATION ; NUMBER ; STRESS ; EPITHELIAL-CELLS ; INVOLVEMENT ; OXIDATIVE STRESS ; INITIATION ; JUNCTIONS ; RE ; DESMOSOMAL PLAQUE ; TRANSLATION ; INTERCELLULAR-JUNCTIONS ; PLAQUE PROTEINS ; BAND-6 PROTEIN ; MENTAL-RETARDATION PROTEIN ; P120 CATENIN ; PROCESSING BODIES ; TRANSLATION INITIATION
    Abstract: Recent studies on the subcellular distribution of cytoplasmic plaque proteins of intercellular junctions have revealed that a number of such proteins can also occur in the cyto- and the nucleoplasm. This occurrence in different, and distant locations suggest that some plaque proteins play roles in cytoplasmic and nuclear processes in addition to their involvement in cell-cell adhesive interactions. Plakophilin (PKP) 3, a member of the arm-repeat family of proteins, occurs, in a diversity of cell types, both as an architectural component in plaques of desmosomes and dispersed in cytoplasmic particles. In immuno-selection experiments using PKP3-specific antibodies, we have identified by mass spectrometric analysis the following RNA-binding proteins: Poly (A) binding protein (PABPC1), fragile-X-related protein (FXR1), and ras-GAP-SH3-binding protein (G3BP). Moreover, the RNA-binding proteins codistributed after sucrose gradient centrifugation in PKP3-containing fractions corresponding to 25-35 S and 45-55 S. When cells are exposed to environmental stress (e.g., heat shock or oxidative stress) proteins FXR1, G3BP, and PABPC1 are found, together with PKP3 or PKP1, in "stress granules" known to accumulate stalled translation initiation complexes. Moreover, the protein eIF-4E and the ribosomal protein S6 are also detected in PKP3 particles. Our results show that cytoplasmic PKP3 is constitutively associated with RNA-binding proteins and indicate an involvement in processes of translation and RNA metabolism
    Type of Publication: Journal article published
    PubMed ID: 16407409
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    Keywords: ACTIN-BINDING ; skin tumors ; keratinocyte ; LOCALIZATION ; tumor ; TUMORS ; INDUCTION ; KERATINOCYTES ; SKIN ; PROTEIN
    Type of Publication: Meeting abstract published
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    Keywords: brain ; DISTINCT ; GENES ; PROTEIN ; COMPLEX ; antibodies ; ARRANGEMENT ; ALPHA-TUBULIN ; ANCIENT EUKARYOTE ; BETA-TUBULIN ; cytoskeleton ; DIVERSITY ; Giardia lamblia ; immunocytochemistry ; MICROTUBULES ; POLYGLYCYLATION ; SUPERFAMILY ; TRYPANOSOMA-BRUCEI ; tubulin
    Abstract: Giardia lamblia is a diplomonad that parasitizes the small intestine of vertebrates. The trophozoite is multiflagellar and its cytoskeleton presents a complex organization of microtubular structures. One of these, the adhesive disk, consists of a microtubular spiral. The median body, whose function is not yet determined, is also composed by microtubules. The cell has eight flagella and two microtubule sheets, known as the funis. In this study we used several antibodies and immunofluorescence microscopy to help in the characterization of these structures. We observed that Giardia tubulin reacts with antibodies raised against very distinct immunogens. The antibodies used were against: (1) alpha-tubulin from chicken embryo brain, Trypanosoma brucei, sea urchin sperm, Paramecium, acetylated alpha-tubulin from Paramecium, and tyrosinated alpha-tubulin, (2) beta-tubulin from chicken embryo brain and Physarum polycephalum, and (3) an antibody with specificity to beta-tubulin having as immunogen the FtsZ bacterial protein. Each cytoskeletal structure of Giardia presented a distinct pattern of labeling by the several antibodies used. These data indicate that even being considered one of the most ancient of organisms, Giardia shares similarities (at least in relation to tubulin) with other organisms. They also open some questions about the organization and composition of its microtubular structures
    Type of Publication: Journal article published
    PubMed ID: 12687378
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    Keywords: CELLS ; IN-VITRO ; SYSTEM ; PROTEIN ; COMPLEX ; ENRICHMENT ; DYNAMICS ; NERVOUS-SYSTEM ; immunohistochemistry ; FIBROBLAST-GROWTH-FACTOR ; ACTIN-BINDING-PROTEIN ; CD2-ASSOCIATED PROTEIN ; CONGENITAL NEPHROTIC SYNDROME ; CONTRACTILE PROTEINS ; DENDRITIC SPINES ; FOCAL SEGMENTAL GLOMERULOSCLEROSIS ; INTERMEDIATE FILAMENT PROTEINS ; SLIT DIAPHRAGM ; ULTRASTRUCTURAL ORGANIZATION
    Abstract: Drebrins are actin-binding proteins (ABP) initially identified in and thought to be specific for neuronal cells, where they appear to contribute to the formation of cell processes. Recent studies have also detected the isoform drebrin E2 in a wide range of non-neuronal cell types, notably in and near actin- rich lamellipodia and filopodia. The present study demonstrates drebrin enrichment in renal glomeruli. Immunohistochemistry and double-label confocal laser scanning microscopy have shown intense drebrin reactions in the mesangial cells of diverse mammalian species. In adult human and bovine kidneys, drebrin is, in addition, markedly enriched in the foot processes of podocytes, as also demonstrable by immunoelectron microscopy. By contrast, the podocytes of rodent glomeruli appear to contain significant drebrin concentrations only during early developmental stages. In differentiated murine podocytes cultured in vitro, however, drebrin is concentrated in the cell processes, where it partially codistributes with actin and other ABP. In biochemical analyses using protein extracts from renal cortices, large (approximately 20S) complexes ("drebrosomes") were found containing drebrin and actin. These findings confirm and extend our hypothesis that drebrin is involved in the regulation of actin dynamics also outside the nervous system. Clearly, drebrin has to be added to the ensemble of ABP regulating the actomyosin system and the dynamics of mesangial cells and foot processes in podocytes
    Type of Publication: Journal article published
    PubMed ID: 12761245
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    Keywords: CANCER ; CELLS ; GROWTH ; GROWTH-FACTOR ; tumor ; carcinoma ; Germany ; human ; MICROSCOPY ; DIAGNOSIS ; PROTEIN ; PROTEINS ; TUMORS ; COMPLEX ; COMPLEXES ; INDUCTION ; KERATINOCYTES ; SKIN ; ASSOCIATION ; immunohistochemistry ; skin cancer ; CARCINOMA-CELLS ; LOCALIZATION ; ADHESION ; intermediate filaments ; CARCINOMAS ; INVOLVEMENT ; squamous cell carcinoma ; beta-catenin ; epidermis ; human hair follicle ; HUMAN EPIDERMIS ; SKIN-CANCER ; CATENIN ; basal cell carcinoma ; HUMAN SKIN ; EPIDERMAL-GROWTH-FACTOR ; INNER-ROOT-SHEATH ; RE ; keratinocyte ; TUMORIGENESIS ; HAIR FOLLICLE ; SKIN CANCERS ; cell adhesion ; hair ; INTERCELLULAR-JUNCTIONS ; BCC ; DESMOSOMAL PLAQUE PROTEINS ; ADHERENS JUNCTIONS ; CELL-CARCINOMA ; E-CADHERIN EXPRESSION ; actin-binding protein ; INTERCELLULAR-ADHESION
    Abstract: Isoform E2 of drebrin, an actin-binding protein originally identified in neuronal cells, has recently been identified in diverse non-neuronal cells, mostly in association with cell processes and intercellular junctions. Here, we report on the presence of drebrin in normal human skin, epithelial skin cancers, and cultured keratinocytes. Keratinocytes of normal epidermis contain almost no drebrin but the protein is readily seen in hair follicles. By immunohistochemistry and immunoblot, basal cell carcinomas (BCC) are rich in drebrin, and confocal laser scanning and immunoelectron microscopy show accumulation at adhering junctions, in co-localization with actin and partially with plaque proteins. In squamous cell carcinomas, keratoacanthomas, and in epidermal precancers, drebrin is heterogeneously distributed, appearing as mosaics. Primary keratinocyte cultures contain significant amounts of drebrin enriched at adhering junctions. When epithelium-derived cells devoid of drebrin are transfected with drebrin-enhanced green fluorescent protein, constructs accumulate in the cell periphery, and immunoprecipitation shows complexes with actin. During epidermal growth factor induced formation of cell processes, drebrin retains this junction association, as observed by live cell microscopy. Our results suggest novel functions of drebrin such as an involvement in cell-cell adhesion and tumorigenesis and a potential value in diagnosis of BCC
    Type of Publication: Journal article published
    PubMed ID: 16185277
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    Keywords: CELLS ; Germany ; human ; PROTEIN ; RNA ; CULTURED-CELLS ; DNA ; CONTRAST ; DYNAMICS ; MELANOMA ; MIGRATION ; cytoskeleton ; LIVING CELLS ; BODY ; ORGANIZATION ; CELL-MIGRATION ; RE ; assembly ; F-ACTIN ; LEVEL ; cell migration ; laminin ; function ; branching ; actin-binding protein ; ACTIN ; FILAMENTS ; MOVEMENTS ; ARP2/3 COMPLEX ; DENDRITIC FILOPODIA ; DEPOLYMERIZING FACTOR ; EDGES ; lamellipodium ; LEADING-EDGE ; microspikes ; MIGRATING CELLS ; MYOSIN-II ; tropomyosin
    Abstract: The actin-binding protein (ABP) drebrin, isoform E2, is involved in remodelling of the actin cytoskeleton and in formation of cell processes, but its role in cell migration has not yet been investigated. Therefore, we have studied the organization of drebrin in motile cultured cells such as murine B16F1 melanoma and human SV80 fibroblast cells, using live cell confocal microscopy. In cells overexpressing DNA constructs encoding drebrin linked to EGFP, numerous long, branched cell processes were formed which slowly retracted and extended, whereas forward movement was halted. In contrast, stably transfected 1316171 cells containing drebrin-EGFP at physiological levels displayed lamellipodia and were able to migrate on laminin. Surprisingly, in such cells, drebrin was absent from anterior lamellipodia but was enriched in a specific juxtanuclear zone, the "drebrin-enriched zone" (DZ), and in the tail. in leading edges of SV80 cells, characterized by pronounced actin microspikes, drebrin was specifically enriched along posterior portions of the microspikes, together with tropomyosin. Drebrin knock-down by small interfering RNAs did not impair movements of SV80 cells. our results confirm the role of drebrin E2 in the formation of branching processes and further indicate that during cell migration, the protein contributes to retraction of the cell body and the tail but not to lamellipodia formation. In particular, the novel, sizable juxtanuclear DZ structure will have to be characterized in future experiments with respect to its molecular assembly and cell biological functions. (c) 2006 Elsevier Inc. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 16780834
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    Keywords: APOPTOSIS ; CELLS ; Germany ; human ; POPULATION ; DISTINCT ; PROTEIN ; PROTEINS ; COMPLEX ; COMPLEXES ; REDUCTION ; STAGE ; mass spectrometry ; FUSION ; MASS-SPECTROMETRY ; POPULATIONS ; INTERACTS ; HEAT-SHOCK PROTEINS ; CHROMOSOMES ; RE ; HELA-CELLS ; LEVEL ; PERSISTENCE ; CHAPERONE ; function ; ESSENTIAL COMPONENT ; PROGRESS ; AURORA KINASES ; Poles ; CENP-E ; CYSTEINE-STRING PROTEIN ; misaligned chromosomes ; prometaphase arrest ; REACTION CYCLE ; REPEAT-CONTAINING PROTEIN ; TPR-CONTAINING PROTEIN
    Abstract: The human small glutamine-rich TPR-containing protein (hSGT) is essential for cell division since RNA-interference-mediated strong reduction of hSGT protein levels causes mitotic arrest (M. Winnefeld, J. Rommelaere, and C. Cziepluch, The human small glutamine-rich TPR-containing protein is required for progress through cell division, Exp. Cell Res. 293 (2004), 43-57). Analysis of HeLa cells expressing a histone 2A-YFP fusion protein revealed the continuous presence of few mislocalized chromosomes close to the spindle poles as possible cause for hSGT depletion-dependent prometaphase arrest. Cells unable to rescue these mislocalized chromosomes into the metaphase plate died at this stage through apoptosis. in order to address hSGT function at the molecular level, mass spectrometry analysis of proteins which co-immunoprecipitated with Flag-tagged hSGT was performed. Thereby, Hsp70 and Bag-6/Bat-3/Scythe were identified as novel hSGT interaction partners while interaction with Hsc70 was confirmed. Results obtained with truncated versions of the hSGT protein revealed that Bag-6/Bat-3/Scythe and Hsp70 or Hsc70 were independently able to form complexes with hSGT. Interaction of hSGT with Hsc70, Hsp70 or Bag-6/Bat-3/Scythe was demonstrated in prometaphase, thereby suggesting a possible role for complexes containing hSGT and distinct (co)-chaperones during mitosis. Finally, cells from populations with reduced levels of Bag-6/Bat-3/Scythe also displayed persistence of mislocalized chromosomes and mitotic arrest, which strongly indicated that hSGT-Bag-6/Bat-3/Scythe complexes could be directly or indirectly required for complete chromosome congression. (c) 2006 Elsevier Inc. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 16777091
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    Keywords: EXPRESSION ; HEPATOCELLULAR-CARCINOMA ; PROTEIN ; PROMOTER ; HETEROZYGOSITY ; MUTATIONS ; WILD-TYPE P53 ; osteosarcoma ; MDM-2 ONCOGENE ; P19(ARF)
    Abstract: The genesis of hepatocellular carcinoma is promoted by changes in the regulatory MDM2-P14ARF system. The incidence of such changes has to date not been analysed in non-tumourous livers showing regenerative proliferation. In the present study, 24 cirrhotic livers of alcohol-, autoimmue disorder- or HCV-caused genesis were screened for MDM2-P14ARF alterations at the level of protein, DNA and mRNA. Using confocal laser scanning microscopy, the absence of MDM2 and P14ARF expression was detected in all samples except three HCV-infected livers (four livers) which contained hepatocytes overexpressing MDM2 (P14ARF) protein. In two of the samples lacking P14ARF expression, laser microdissection and PCR demonstrated deletion of the P14ARF gene. The P14ARF gene amplified from other specimens did not carry mutations. MDM2 splicing variants were present in tissues from alcohol- and autoimmune disorder-induced cirrhoses. Sequencing of full-size mRNA revealed a MDM2 mis-sense mutation in an alcohol-induced cirrhosis. One sample contained regenerative nodules with genetic instability occurring at MDM2 locus D12S83 according to the data of automatic PCR fragment analysis. In summary, this study gives first evidence for different types of MDM2 and P14ARF alterations in cirrhotic livers. We suggest that the changes impair the regulatory MDM2-P14ARF system, thus possibly favouring regenerative proliferation and transformation.
    Type of Publication: Journal article published
    PubMed ID: 11953887
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    Keywords: PROTEIN ; MEMBRANE ; NEUTRON-CAPTURE THERAPY ; gadolinium
    Abstract: Molecular imaging is defined as the characterization and measurement of biological processes at the cellular and molecular level. Molecular imaging, therefore, necessitates a sufficient amount of contrast agent within the cell. Consequently, we realized that the intracellular uptake and cell compartment specificity of the commonly used interstitial contrast agent gadolinium (Gd(3+)) with a cell-nucleus directed peptide module could be helpful. This modular molecule is characterized by a Gd(3+)-complex module that is bound to a transmembrane transport unit (TPU) of human origin and further to a nucleus-directed address module (nuclear localization sequence) resulting in a specific cell nucleus-directed nuclear localization sequence-conjugated Gd(3+)-complex (CNN-Gd(3+)-complex). By use of magnetic resonance imaging, Gd(3+) was detected within DU-145 prostate cancer cells after only 10 min. The nuclear localization was confirmed with confocal laser scanning microscopy. The resulting MRI signal enhancement only slightly decreased over the next 48 h compared with an absolute loss of signal enhancement after only 8 h when a random target sequence was used. Therefore, our method seems promising for in vivo application in molecular imaging.
    Type of Publication: Journal article published
    PubMed ID: 12460922
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...