PubMed Health⌕ Search

Biomedical subjects

M Takeichi

Publications and source records attributed to M Takeichi.

At least 91 records · Page 5Linked to original sources
PubMed1995

Solution structure of the epithelial cadherin domain responsible for selective cell adhesion.

Cadherins are calcium-dependent cell adhesion molecules containing extracellular repeats of approximately 110 amino acids. The three-dimensional structure of the amino-terminal repeat of mouse epithelial cadherin was determined by multidimensional heteronuclear magnetic resonance spectroscopy. The calcium ion was bound by a short alpha helix and by loops at one end of the seven-stranded beta-barrel structure. An exposed concave face is in a position to provide homophilic binding specificity and was also sensitive to calcium ligation. Unexpected structural similarities with the immunoglobulin fold suggest an evolutionary relation between calcium-dependent and calcium-independent cell adhesion molecules.

Amino Acid Sequence↗
PubMed1995

Altered expression and function of E-cadherin in cervical intraepithelial neoplasia and invasive squamous cell carcinoma.

HECD-1 monoclonal antibody has been used to localize E-cadherin, a calcium-dependent cell-cell adhesion molecule, in microwave-treated, paraffin-embedded sections from 53 cases of cervical intraepithelial neoplasia (CIN) (11 CIN I, 22 CIN II, and 20 CIN III), 16 invasive cervical squamous cell carcinomas, and seven metastases. In normal cervix, E-cadherin was expressed on the cell membrane of basal and parabasal cells. Cytoplasmic staining was present in occasional basal cells only. In CIN, the presence and localization of cytoplasmic E-cadherin were found to be significantly correlated with the grade of the CIN lesion. In squamous cell carcinomas, reduced membranous and increased cytoplasmic staining was seen with worsening differentiation. Loss of membranous E-cadherin expression was also detected in 4/7 metastatic deposits. E-cadherin expression (120 kD form on Western blotting) was seen in human cervical carcinoma cell lines (HT3, ME180, C4I, Caski) that maintained the ability to aggregate in a homotypic adhesion assay and showed a typical epithelial morphology. E-cadherin-negative cell lines (Hela, SiHa, C33A) did not show adhesion. HOG-1 was the only E-cadherin-negative cell line which showed a significant degree of cell-cell aggregation. These data indicate that loss of membranous E-cadherin expression may represent one of the abnormalities underlying loss of cell polarity and differentiation which characterize CIN and invasive cervical cancer.

Blotting, Western↗
PubMed1995

Cadherin-11 expressed in association with mesenchymal morphogenesis in the head, somite, and limb bud of early mouse embryos.

Cadherin-11 (cad-11) is a novel member of the cadherin family of cell adhesion molecules, having recently been identified by means of the polymerase chain reaction. To study the function and expression of this molecule, we cloned mouse, cad-11 cDNA. Transfection of L cells with cDNA led them to acquire a typical cadherin-dependent cell-cell adhesiveness, and the L cells expressing cad-11 did not coaggregate with L cells expressing E-, P-, N-, or R-cadherin when they were mixed, indicating that this novel cadherin has a homophilic binding specificity, as found for other cadherins. To determine the developmental expression pattern of this molecule, we performed in situ hybridization analysis on early mouse embryos. Cad-11 first appeared in mesodermal layers only in the head and tail regions at the mid-to-late primitive streak stages. In the head, this appearance was followed by strong expression in mesenchymal tissues including branchial arches. In the trunk, the paraxial mesoderm initially did not express cad-11. However, as the somites formed, they expressed cad-11, and this expression was strictly correlated with their initial condensation and segregation from the presomitic mesoderm. The cad-11 expression in the somites was eventually restricted to sclerotome cells. As the limb buds developed, cad-11 appeared in the distal portion of the limb mesenchyme, and, at later stages, its expression was most evident at the peripheral mesenchyme. Cad-11 was thus expressed by restricted populations of mesenchymal cells in early embryos, although it was also expressed in parts of the neural tube, such as the optic vesicle and dorsal midline, and in part of the otic vesicle. As a step to investigate the role of cad-11 in mesenchymal cell adhesion, we dissociated the limb bud mesenchyme into single cells, pelleted them, and cultured them as aggregates. In these cultures, cad-11-positive cells clearly sorted out of the negative cell population, suggesting that cad-11 might be involved in selective association of mesenchymal cells. For comparison, we studied the expression of N-cadherin and found that the expressions of these two cadherins were differential, and complementary in some tissues. These results suggest that cad-11 is involved in specific associations of subsets of mesenchymal cells and also of some neural cells during early embryogenesis.

Amino Acid Sequence↗
PubMed1995

Fetal brain subdivisions defined by R- and E-cadherin expressions: evidence for the role of cadherin activity in region-specific, cell-cell adhesion.

We found that R-cadherin, a Ca2(+)-dependent cell--cell adhesion molecule, is expressed in restricted regions of the mouse fetal brain, as was found for E-cadherin previously. R-cadherin delineated a subset of alar domains within forebrain neuromeres and certain future nuclei, while E-cadherin was expressed in another distinctive pattern. When cells were collected from various local regions of the fetal brain, dissociated, and reaggregated under the conditions in which only cadherins are active for cell aggregation, R-cadherin-positive and -negative cells segregated from one another. Similar results were obtained for E-cadherin. Such segregation of cells was, however, suppressed when the cadherins were inactivated either by Ca2+ depletion or with blocking antibodies. These results suggest that cadherins confer region-specific adhesiveness on fetal brain cells and that this process may take part in brain segmentation.

Animals↗
PubMed1995

Doctor-shopping patients and users of alternative medicine among Japanese primary care patients.

To describe the clinical characteristics of patients with doctor-shopping behavior (doctor-shopping patients) and users of alternative medicine among Japanese primary care patients, 1088 patients from the general medicine outpatient clinic of a medical school hospital answered an original questionnaire and 30-item General Health Questionnaire (GHQ). A random sample of patients was questioned in accordance with the Diagnostic Interview Schedule modified for use in Japan (DIS-JM). Twenty-three percent of these patients met our criteria for doctor-shopping patients, and 7.9% had used alternative medicine. Multivariate analysis showed no significant difference between the two groups of patients with regard to sex, age, residence, occupation, education, or marital status. The most striking characteristics of doctor-shopping patients were chronicity of illness (p < 0.005), inability to understand doctors' explanations (p < 0.005), disbelief of the doctor's diagnosis and treatment (p < 0.005), and high GHQ scores (p < 0.05). The major factor for alternative medicine users was high expectations of medical school hospitals (p < 0.01). DIS-JM interviews showed that doctor-shopping patients had a high lifetime prevalence of mental disorders. The lifetime prevalence of DSM-III somatization disorders was significantly higher in the two study groups. These results suggest that the risk factors for doctor shopping are strongly associated with chronic conditions and the doctor-patient relationship. Also, users of alternative medicine had high expectations of medical school hospitals as the symbol of modern medicine. Therefore, we emphasize the importance of accurate explanations and maintenance of good doctor-patient relationships by physicians providing care. We also suggest that when obtaining the patient's medical history, doctors ask how many prior visits the patient has made to medical facilities with the same complaint, and how many times the patient has used alternative medicine.

Adolescent↗
PubMed1995

Localization of N-cadherin in the normal and regenerating nerve fibers of the chicken peripheral nervous system.

The localization of N-cadherin in the normal, and regenerating nerve fibers was investigated by immunocytochemistry in the chicken sciatic nerve. The normal unmyelinated fibers exhibited N-cadherin immunoreactivity on the plasma membranes of axons and Schwann cells where they were in contact with each other, while myelinated fibers displayed no immunoreactivity except at the mesaxon where Schwann cell plasma membranes were attached to each other. In the regenerating nerves, intense immunoreactivity was demonstrated on the surface of plasma membranes of axons and Schwann cells where axon-axon and axon-Schwann cell contacts were made. No immunoreactivity was observed on the plasma membranes where regenerating axons or Schwann cells were in touch with the basal lamina. In addition, it was revealed that some vesicles in the growth cones had distinct N-cadherin immunoreactivity at the inner limiting membrane surface. These findings indicate that N-cadherin may be involved in the axon-axon and axon-Schwann cell adhesion in the normal unmyelinated as well as regenerating nerve fibers, and also in the attachment of Schwann cell processes at the mesaxon of myelinated fibers. In addition, these findings suggest that N-cadherin might be, at least in part, supplied by fusion of growth cone vesicles with the surface plasma membranes in growing axons.

Animals↗
PubMed1995

Morphogenetic roles of classic cadherins.

Classic cadherins, which are known to be crucial for homotypic cell-cell adhesion, have been found to be present not only in vertebrate but also in invertebrate species. Their three-dimensional structures, novel functions, and novel expression patterns were reported recently. These have been important steps towards a deeper understanding of the morphogenetic roles of this family of molecules.

Animals↗
PubMed1995

Effect of epidermal growth factor on cadherin-mediated adhesion in a human oesophageal cancer cell line.

Epidermal growth factor (EGF) mediates many pleiotrophic biological effects, one of which is alteration of cellular morphology. In the present study, we examine the possibility that this alteration in cell morphology is caused in part by the dysfunction of cadherin-mediated cell-cell adhesion using the human oesophageal cancer cell line TE-2R, which expresses E-cadherin and EGF receptor. In the presence of EGF, TE-2R changed its shape from round to fibroblastic and its colony formation from compact to sparse. Vanadate, a tyrosine phosphatase inhibitor, further potentiated the EGF response, whereas herbimycin A, a tyrosine kinase inhibitor, interfered with it. Moreover, EGF enabled the cells to invade in organotypic raft culture. These phenomena were accompanied not by decreased expression of the E-cadherin molecule but by a change in its localisation from the lateral adhesion site to the whole cell surface. Both alpha- and beta-catenin, cadherin-binding proteins, were also expressed at the same level throughout these morphological changes. Finally, we examined tyrosine phosphorylation of E-cadherin and alpha- and beta-catenin, and observed tyrosine phosphorylation of beta-catenin induced by EGF. These results suggest that EGF counteracts E-cadherin-mediated junctional assembly through phosphorylation of beta-catenin and modulates tumour cell behaviour to a more aggressive phenotype.

Benzoquinones↗
PubMed1995

Association of p120, a tyrosine kinase substrate, with E-cadherin/catenin complexes.

p120 was originally identified as a substrate of pp60src and several receptor tyrosine kinases, but its function is not known. Recent studies revealed that this protein shows homology to a group of proteins, beta-catenin/Armadillo and plakoglobin (gamma-catenin), which are associated with the cell adhesion molecules cadherins. In this study, we examined whether p120 is associated with E-cadherin using the human carcinoma cell line HT29, as well as other cell lines, which express both of these proteins. When proteins that copurified with E-cadherin were analyzed, not only alpha-catenin, beta-catenin, and plakoglobin but also p120 were detected. Conversely, immunoprecipitates of p120 contained E-cadherin and all the catenins, although a large subpopulation of p120 was not associated with E-cadherin. Analysis of these immunoprecipitates suggests that 20% or less of the extractable E-cadherin is associated with p120. When p120 immunoprecipitation was performed with cell lysates depleted of E-cadherin, beta-catenin was no longer coprecipitated, and the amount of plakoglobin copurified was greatly reduced. This finding suggests that there are various forms of p120 complexes, including p120/E-cadherin/beta-catenin and p120/E-cadherin/plakoglobin complexes; this association profile contrasts with the mutually exclusive association of beta-catenin and plakoglobin with cadherins. When the COOH-terminal catenin binding site was truncated from E-cadherin, not only beta-catenin but also p120 did not coprecipitate with this mutated E-cadherin. Immunocytological studies showed that p120 colocalized with E-cadherin at cell-cell contact sites, even after non-ionic detergent extraction. Treatment of cells with hepatocyte growth factor/scatter factor altered the level of tyrosine phosphorylation of p120 as well as of beta-catenin and plakoglobin. These results suggest that p120 associates with E-cadherin at its COOH-terminal region, but the mechanism for this association differs from that for the association of beta-catenin and plakoglobin with E-cadherin, and thus, that p120, whose function could be modulated by growth factors, may play a unique role in regulation of the cadherin-catenin adhesion system.

Binding Sites↗
PubMed1995

Delayed assembly of desmosomes in keratinocytes with disrupted classic-cadherin-mediated cell adhesion by a dominant negative mutant.

We examined whether classic cadherins play a role in the formation of desmosomes using a mouse keratinocyte, PAMcN390 delta cell, which shows disrupted classic-cadherin-mediated cell adhesion by introduction of a dominant-negative mutant of N-cadherin. The expression of the mutant did not alter that of endogenous E-cadherin or desmoplakin. In control cells with functional classic cadherins, we observed redistribution of desmoplakin to cell-cell borders with insertions of keratin filaments at the contact sites as soon as 2 h after calcium elevation, after an earlier event of E-cadherin translocation to the cell-cell contact sites. In contrast, in the PAMcN390 delta cells, which showed retarded translocation of E-cadherin, the redistribution of desmoplakin and the rearrangement of keratin filaments were delayed as late as 24 h after the calcium elevation. The acquisition of Nonidet P-40 insolubility of desmoplakins also was found to be delayed in the PAMcN390 delta cells. These findings indicate that the disruption of classic cadherin affected the organization of desmosomes upon calcium elevation and suggest that the proper function of classic cadherins is a prerequisite for desmosome assembly in keratinocytes.

Animals↗
PubMed1995

Neural crest cell-cell adhesion controlled by sequential and subpopulation-specific expression of novel cadherins.

We identified two cadherins, c-cad6B and c-cad7, expressed by neural crest cells at their premigratory and migratory stages, respectively, in chicken embryos. cDNA transfection experiments showed that both were homophilic adhesion molecules, endowing cells with specific adhesiveness. During development, c-cad6B appeared in the neural fold, localizing at the future neural crest area. This expression was maintained during neural tube closure, but disappeared after neural crest cells had left the neural tube, suggesting its role in neural fold fusion and/or in the formation and maintenance of the presumptive neural crest domain in the neural plate/tube. Crest cells emerging from the neural tube lost c-cad6B, and a subpopulation of them began to express c-cad7. This subpopulation-specific expression of c-cad7 persisted during their migration. The migrating c-cad7-positive cells clustered together, and eventually populated restricted regions including the dorsal and ventral roots but very little ganglia. The latter was populated with N-cadherin-positive crest cells. Migrating neural crest cells expressed alpha- and beta-catenin at cell-cell contacts, indicating that their cadherins are functioning. These results suggest that the migrating crest cells are grouped into subpopulations expressing different cadherins. The cadherin-mediated specific interaction between crest cells likely plays a role in intercellular signaling between homotypic cells as well as in sorting of heterotypic cells.

Amino Acid Sequence↗
PubMed1994

Purification and spectroscopic characterization of a recombinant amino-terminal polypeptide fragment of mouse epithelial cadherin.

Cadherins are a family of Ca(2+)-dependent cell adhesion molecules containing four extracellular tandem repeats each of 110 amino acids. The most amino-terminal repeat is believed to confer the specificity of cell adhesion. A polypeptide containing the amino-terminal repeat of mouse epithelial cadherin has been over-expressed in E. coli and purified to homogeneity. This polypeptide binds Ca2+ with a dissociation constant of 1.6 x 10(-4) M. CD and NMR experiments indicate that the polypeptide adopts a predominantly beta-sheet conformation and that binding of Ca2+ induces only small conformational changes.

Amino Acid Sequence↗
PubMed1994

Experimental specification of cell sorting, tissue spreading, and specific spatial patterning by quantitative differences in cadherin expression.

The sorting-out of embryonic cells from a cell mixture and the selective spreading of one cell population over the surface of another have been attributed to various causes. These include differentials in chemotaxis, in cellular adhesiveness, in cell surface contractility, in speed of cell movement, and in the timing of postulated changes in cellular adhesive and motile properties. One of us earlier predicted on mathematical grounds that two motile cell types differing only in the level of expression of a single cell adhesion system should not only segregate from one another but also arrange themselves with the less cohesive cells enveloping a core of the more cohesive ones. To test these predictions, we combined two populations of L cells transfected with P-cadherin cDNA and expressing this homophilic adhesion molecule in substantially differing amounts. When the two cell populations were intermixed, they segregated to approach a sphere-within-a-sphere configuration, the cell population expressing more P-cadherin forming islands which fused to become an internal "medulla." When the two cell populations were first formed into separate aggregates which were subsequently allowed to fuse, the cell population expressing more P-cadherin was enveloped by its partner, which formed an external "cortex." These observations confirm the early prediction and support the conclusion that both morphogenetic movements and the specific anatomical configurations to which they lead can be determined by particular sets of intercellular adhesive intensities, regardless of how these are generated and in the absence of differentials in other parameters.

Animals↗
PubMed1994

Loss of membranous E-cadherin expression in pancreatic cancer: correlation with lymph node metastasis, high grade, and advanced stage.

Epithelial cadherin (E-cadherin) is a Ca(2+)-dependent cell-cell adhesion molecule that connects cells via homotypic interactions. Its function is critical in the induction and maintenance of cell polarity and differentiation, and its loss of downregulation is associated with an invasive and poorly differentiated phenotype in colon and other tumors. We have used an avidin-biotin immunoperoxidase technique to localize E-cadherin in microwave-treated, paraffin-embedded sections from 36 patients with pancreatic adenocarcinomas. E-cadherin was expressed by normal ductal and acinar cells with typical membranous staining at the intercellular junctions. Loss of normal surface E-cadherin expression was found in 19/36 (53 per cent) tumours compared to the adjacent normal ductal cells. Abnormal E-cadherin expression was found more frequently in poorly differentiated (grade III) (6/7, 86 per cent) than in well-differentiated tumors (grade I) (4/14, 28 per cent) (P = 0.012). Membranous E-cadherin expression was also lost more frequently in primary tumours with lymph node (stage III) (14/23, 61 per cent) and distant metastasis (stage IV) (2/2, 100 per cent) compared with 3/11 (27 per cent) lymph node-negative tumours (stage I) (P = 0.043). In conclusions, our data indicate that loss of membranous E-cadherin expression is associated with high grade and advanced stage in pancreatic cancer.

Adenocarcinoma↗
PubMed1994

Mouse alpha N-catenin: two isoforms, specific expression in the nervous system, and chromosomal localization of the gene.

We isolated cDNAs encoding mouse homologues of chicken alpha N-catenin, a protein associated with the cadherin cell adhesion molecules, and identified two isoforms of this protein. One isoform (alpha N-catenin I) was identical to the chicken alpha N-catenin that had previously been identified, and the other (alpha N-catenin II) differed in having a 48-amino acid insertion in its C-terminal region. The ratio of the two isoforms changed during development; the isoform II was more abundant than the other in earlier embryonic stages, whereas isoform I was predominant in the adult stage. Immunostaining and in situ hybridization analyses revealed that the mouse alpha N-catenin was expressed almost exclusively in the nervous system. During embryogenesis, alpha N-catenin was first detected in nerve fibers of cranial and dorsal root ganglia and also in early neurons in the neural tube, including motor neurons. Thereafter, the expression of this protein occurred in various regions of the nervous system. Neurons, in general, strongly expressed alpha N-catenin, especially in their axonal fibers. On the other hand, the expression in glial cells varied with the region. For example, the ependymal layers of the neural tube generally expressed low levels of alpha N-catenin except at the inner limiting membrane facing the central canal, whereas the floor and roof plate exhibited strong expression of this protein at various portions of the central nervous system. The choroid plexus was devoid of alpha N-catenin. In the alpha N-catenin-negative regions, another subtype of alpha-catenin, alpha E-catenin, was expressed. Concerning nonneural tissues, alpha N-catenin was expressed only in some local mesenchymal cell clusters and the lens fibers. These results suggest that alpha N-catenin plays specific roles in neural cell-cell interactions. We also localized the mouse alpha N-catenin gene to chromosome 6.

Amino Acid Sequence↗
PubMed1994

A Drosophila homolog of cadherin associated with armadillo and essential for embryonic cell-cell adhesion.

We have identified a Drosophila homolog of vertebrate classic cadherins. A monoclonal antibody to Drosophila alpha-catenin (D alpha-catenin) copurifies a 150-kDa glycoprotein (gp150) along with the alpha-catenin. To further characterize this protein, we generated monoclonal antibodies to gp150 and isolated its cDNAs using the antibodies. Predicted sequences of the encoded product revealed that it is a transmembrane protein with similarity to vertebrate classic cadherins, and so we designated this molecule DE-cadherin. The extracellular domain has six cadherin-specific repeats, although the first repeat seems to be cleaved off upon maturation, and the cytoplasmic domain shows significant identity to that of vertebrate classic cadherins. DE-cadherin is distinguishable from its vertebrate counterparts by a large insertion with local sequence similarity to Fat, laminin A chain, Slit, and neurexin I at the proximal region of the extracellular domain. Despite such differences, DE-cadherin is functionally similar to vertebrate classic cadherins. For example, it is associated with alpha-catenin and beta-catenin (Armadillo), and protected from trypsin digestion only in the presence of Ca2+, as is the case for many of classic cadherins. Transfection of S2 cells with the DE-cadherin cDNA enhances their Ca(2+)-dependent cell aggregation. Antibodies to this molecule inhibited aggregation of not only the transfectants but also early embryonic cells. DE-cadherin is concentrated at the apical poles of epithelial cell-cell junctions. All these results suggest that DE-cadherin is a homolog of vertebrate classic cadherins and that the vertebrate and invertebrate share common mechanisms for regulation of cell-cell adhesion.

Amino Acid Sequence↗
PubMed1994

Immunoelectron microscopic localization of E-cadherin in dorsal root ganglia, dorsal root and dorsal horn of postnatal mice.

Sensory neurons and associated glial cells are known to express the cell-cell adhesion molecule E-cadherin. The cellular and subcellular localization of this molecule in the dorsal root ganglion, dorsal root, and spinal cord of postnatal mice was studied by the pre-embedding immunoelectron microscopic labelling technique. In the dorsal root and the superficial layer of the dorsal horn, a subset of fasciculating unmyelinated axons expressed E-cadherin at their axon-axon contacts at all ages studied, and these axons were clustered together and segregated from E-cadherin-negative axons. In contrast, pre-myelinating large-diameter axons in P2 mice as well as myelinated axons in mice from P14 to adulthood were E-cadherin-negative. Glial cells also expressed E-cadherin: In the dorsal root ganglia, all of the satellite cells expressed E-cadherin at contact sites with neurons, other satellite cells, and basal lamina, at all ages studied. In dorsal roots from P14 to adulthood, myelin-forming Schwann cells expressed E-cadherin at the outer mesaxons and the contact sites with basal lamina. Non-myelin-forming Schwann cells occasionally stained for this molecule at contact sites with the plasma membrane of E-cadherin-positive axons and at other sites. These results strongly suggest that E-cadherin plays an important role in the selective fasciculation of a particular subset of unmyelinated sensory fibres, and also in glial cell contacts.

Animals↗