Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Keywords: CELLS ; EXPRESSION ; tumor ; BLOOD ; carcinoma ; human ; MICROSCOPY ; liver ; PROTEIN ; PROTEINS ; TUMORS ; FAMILY ; RAT ; hepatocytes ; MEMBER ; MEMBERS ; antibodies ; MOUSE ; IDENTIFICATION ; RAT-LIVER ; MEMBRANE ; metastases ; CONJUGATE ; LOCALIZATION ; EPITHELIAL-CELLS ; HEPATOCYTE CANALICULAR ISOFORM ; METASTATIC CARCINOMAS ; MULTIDRUG-RESISTANCE PROTEIN ; POLYPEPTIDE OATP2
    Abstract: Transport proteins mediating the selective uptake of organic anions into human hepatocytes include the organic anion transporters SLC21A6 (also termed OATP2, OATP-C, or LST-1) and SLC21A8 (OATP8). Both transporters are localized to the basolateral membrane of human hepatocytes. Because of the importance of these transporters for hepatobiliary elimination, including the removal of bilirubin and its conjugates from the blood circulation, we have generated monoclonal antibodies for studies on the expression and localization of these transport proteins. We describe two antibodies, designated monoclonal antibody MDQ (mMDQ) and monoclonal antibody ESL (mESL), directed against the amino terminus and the carboxyl terminus of human SLC21A6, respectively. Both antibodies have been characterized by immunoblot analysis, immunoprecipitation, and immunofluorescence microscopy. While mESL reacted specifically with SLC21A6, mMDQ detects both SLC21A6 and SLC21A8. Neither of the two antibodies reacted with other human, or with dog, rat, or mouse liver SLC21A family members. Antibody mMDQ may be used for the simultaneous detection of SLC21A6 and SLC21A8 in immunoblotting because of its immunoreactivity with both molecules and because of the different molecular masses of both glycosylated proteins in human hepatocytes. This is exemplified in hepatocellular carcinomas where SLC21A6 and SLC21A8 were differentially synthesized and showed an irregular staining pattern. Both transport proteins have not been detected in human hepatoma HepG2 cells. In routine paraffin sections, 10 of 12 hepatocellular carcinomas were focally positive with antibody mMDQ. In contrast, cholangiocarcinomas and liver metastases of colorectal and pancreatic adenocarcinoma were negative without exception. This suggests the usefulness of SLC21A6/SLC21A8 within a panel of tumor markers for hepatocellular carcinomas. Moreover, both antibodies should be useful in studies on the expression and localization of two important uptake transporters of human hepatocytes under physiologic and pathophysiologic conditions
    Type of Publication: Journal article published
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    Keywords: PEPTIDE ; CELLS ; IN-VITRO ; CELL ; human ; VITRO ; PROTEIN ; DOMAIN ; BIOLOGY ; SPECTROSCOPY ; FORM ; SUBUNIT ; MUTATION ; CRYSTAL-STRUCTURE ; STABILITY ; INTERMEDIATE-FILAMENTS ; vimentin ; DIMER ; lamin ; DOMAINS ; ATOMIC-STRUCTURE ; intermediate filament ; SINGLE ; molecular biology ; assembly ; REARRANGEMENT ; coiled coil ; COILED-COIL ; nuclear lamins ; TEMPERATURE ; AMINO-ACID SUBSTITUTIONS ; circular dichroism ; POSITION ; STATE ; biophysical analysis ; CONSENSUS MOTIF ; GCN4 LEUCINE-ZIPPER ; HYDROPHOBIC CORE ; Oligomerisation ; OLIGOMERIZATION STATE ; PROTEIN STRUCTURES
    Abstract: Interestingly, our previously published structure of the coil 1A fragment of the human intermediate filament protein vimentin turned out to be a monomeric alpha-helical coil instead of the expected dimeric coiled coil. However, the 39-amino-acid-long helix had an intrinsic curvature compatible with a coiled coil. We have now designed four mutants of vimentin coil 1A, modifying key a and d positions in the heptad repeat pattern, with the aim of investigating the molecular criteria that are needed to stabilize a dimeric coiled-coil structure. We have analysed the biophysical properties of the mutants by circular dichroism spectroscopy, analytical ultracentrifugation and X-ray crystallography. All four mutants exhibited an increased stability over the wild type as indicated by a rise in the melting temperature (T-m). At a concentration of 0.1 mg/ml, the T-m of the peptide with the single point mutation Y117L increased dramatically by 46 degrees C compared with the wild-type peptide. In general, the introduction of a single stabilizing point mutation at an a or a d position did induce the formation of a stable dimer as demonstrated by sedimentation equilibrium experiments. The dimeric oligomerisation state of the Y117L peptide was furthermore confirmed by Xray crystallography, which yielded a structure with a genuine coiled-coil geometry. Most notably, when this mutation was introduced into full-length vimentin, filament assembly was completely arrested at the unit-length filament (ULF) level, both in vitro and in cDNA-transfected cultured cells. Therefore, the low propensity of the wild-type coil 1A to form a stable two-stranded coiled coil is most likely a prerequisite for the end-to-end annealing of ULFs into filaments. Accordingly, the coil 1A domains might "switch" from a dimeric alpha-helical coiled coil into a more open structure, thus mediating, within the ULFs, the conformational rearrangements of the tetrameric subunits that are needed for the intermediate filament elongation reaction. (C) 2009 Elsevier Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 19422834
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    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 ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...